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General Information => General => Topic started by: clbanman on August 12, 2008, 07:21:00 pm
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Did all VW's come with the vacuum assist brakes? I'm used to older North American iron with power steering but manual brakes. Is it possible to "downgrade" your brakes and would there be any advantage to doing so? I'm thinking potential reduction in things that can go wrong. Fewer parts, fewer potential issues. Am I way off base or wasting my time?
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I don't know if it means anything, but the donor engine for my diesel Fox came out of a '79 Rabbit that didn't have a vacuum pump. And I swear I cracked the original bolt holding the cap over the intermediate shaft end.
Had a neat little gear to drive the oil pump, a cap for the hole, the usual pump holder, and an o-ring seal.
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just unhook the hose going to the power booster and drive it around and see if you like it that way? i don't think you will!
but i know what you mean! i just bought a jeep and it has no powerbooster but i sure wish it did! the pedal is hard and does not stop hardly at all!
Duane
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Just disconnecting the booster isn't correct if the system is designed for vacuum assist. There are usually differences in the design for leverage and hydraulic ratios if the system is designed to be used without a vacuum boost. It would be similar to disconnecting the belt to a power steering pump and thinking that's what manual steering feels like.
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why would you take a beautifully engineered, low maintenance item and turn it into something that can kill you?
just upgrade your system, 236mm discs are only good for a unladen 1.3 in my view.
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FYI Jake, FSPGTD on here, ran his autocrosser Rabbit with manual brakes. Search for his posts and you'll probably find a few of them. He did have an upgraded system and an adjustable proportioning valve but it was a manual system.
Brendan
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why would you take a beautifully engineered, low maintenance item and turn it into something that can kill you?
Well, for one, while I haven't had any issues, I have seen numerous posts on this forum from guys who have had booster or vacuum pump problems, so potentially eliminating that. I have absolutely no intention of turning this into something that can kill me, which is why I'm asking questions before I do anything (if I ever do). I personally prefer the pedal feel on a properly set up manual brake system and feel that modulation and threshhold braking are easier for me to feel and control. I have a 67 Ford Galaxie that I have no issues stopping with manual brakes, so a properly set up system could be simpler and possibly give me the feel I prefer.
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ok, I know that for competition purposes the manual setup is preferred (VWM used it on the rally Golf and endurance Bora), and if well done its a matter of preference.
I was just trying to pass the message that brakes are one thing that has do be done properly or lives get at risk.
I also like the hard pedal feel, but I know that eventually my mother will need to borrow my car, and I doubt she will have enough force to use the brakes, or sensitivity to modulate them to avoid locking..
I decided for the opposite aproach: brake setup from a much bigger car (passat vr6) and a concealed switch to disable ABS and EDS when I want to burn some rubber.
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I'm keeping my power brakes on my 1.6 turbo Caravan build-up, but I switched the power steering out for a new manual rack & pinion. The PS uses much more energy than power brakes. Also, the caravan is a tad larger than the VW.
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FYI Jake, FSPGTD on here, ran his autocrosser Rabbit with manual brakes. Search for his posts and you'll probably find a few of them. He did have an upgraded system and an adjustable proportioning valve but it was a manual system.
Brendan
My understanding is that disc brakes pretty much need a brake booster to be of any use since the calipher pistons provide very little mechanical advantage (tiny lever effect) unlike drum brakes where the slave cylinder acts against long shoes (big lever effect)
People that I know that remove the brake booster also convert back to front drums... as was available on the early Rabbits.
Dunno if that's what Jake did... but he might have done. Haven't followed competitive rallying for a while now so maybe they've figured it out with disks as well.
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If you want manual brakes on a VW, just find a manual setup from a Mk1 Rabbit or Jetta. 17mm master cylinder, the push rod to the master is on the brake pedal at a different pivot point. If you have the old bentley manuals they will show you the dimension differences.
Or, you could make a twin master setup using wilwood or tilton masters with a threaded balance bar like on a race car.
I'm not sure what setup Jake has on his FSP rabbit. My SM turned FSP Scirocco lost the booster and went manual to loose the weight and get a more consistent pedal. No vacuum from a gas motor at WFO throttle. Diesel will have vacuum to operate the booster no matter what. Curious how much power is taken from the motor to produce that vacuum tho. Competitive autocrossers do stuff different than daily drivers. Best pedal feel I've driven used a 22mm master with booster (like 16V or late 80's-90 cabrio) steel braided lines and good brake pads. Even better than that was a Mk4 Jetta, all stock.
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makes sense... you just need a different pivot point for more leverage, and a smaller master cylinder. because you will need more travel to get the same movement in the calipers/cylinders.
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Chevettes came with non assist brakes and they have front calipers (I think)
My brothers seems to stop just fine, you definitly can tell it isn't power assist though
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i think theres an added security benefit to it... what if your power assisted brakes suddently went off??? either from a vacuum leak, booster failure, or engine shut down?
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The booster is designed to "assist" 2 or more pedal applications once the engine is off, or if the vacvuum pump exploded
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pedal feel gets REAL hard, but will continue to brake
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My vacuum pump is leaking so sometimes I will get a soft pedal feel with good stopping, and sometimes I will have to put my whole body into the brake pedal to stop the car. I've been wondering how to get rid of the vacuum assist also to get a consistent pedal feel and free up a tiny bit of weight and power. And a cleaner engine bay.
So all that is needed is a manual brake pedal setup and a smaller master cylinder?
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If you don't want to reduce your car's braking performance, you have to look at the whole system. Only use the smaller master cylinder if it is factory matched to the pedal setup. If you don't change your calipers, putting in a smaller master cylinder will reduce your brake force UNLESS you increase the travel of the piston in the master cylinder. You could keep your existing master cylinder and change the lever point on your brake pedal (mechanical advantage) to retain similar braking performance without greatly increased pedal effort. I don't know VW's well enough to know what factory available setups there were with manual brakes. Ideally you would use a complete system from a car with similar or higher weight, or properly engineer it from aftermarket parts to increase braking performance. The cheapest way is usually to get an entire system from a factory higher performance version of the car you are driving, or a similar but heavier car made by the same manufacturer. Some brands have more mix and match choices than others.
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So all that is needed is a manual brake pedal setup and a smaller master cylinder?
pretty much, just get all the manual parts off a Mk1 Rabbit. Use stock front calipers, no need to hunt down front drums.
The Rabbit I drove at the Atlanta Doublecross, Pro Solo has the manual pedal, manual master, rabbit gti kelsey hayes front caliper, (same as Mk2 caliper) drum rear, a manual proportioning valve to adjust bias, and forgot what pads. Might be Hawk HP plus or HP street or carbotech panther. Granted the car weighs less than a Mk2 by A LOT!!!, but the pedal feel was just fine and the car did stop.
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yes the early mkIs came that way, non-power brakes. yes you can fit those parts just fine (pedal cluster, non-power master cylinder) but i believe it will also involve bending new brakes lines for the new MC position. totally reasonable and safe modification. i'm with you... less stuff to break, better feel. as mentioned, the majority of the competitive mkIs use non-power brakes (but not the VW stuff).
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I can't believe people are talking about wanting NON servo assisted brakes... :shock:
I used to have a 92 VW Polo (small small car, think it's smaller than a rabbit) which didn't have servo brakes. It seemed okay at the time but when I drove it after having driven again a car with proper brakes, it was scary.
Non servo brakes might seem fine when driving normally but during an emergency stop under load on a steep downhill, you'll be crapping yourself. Just before you die, that is. That's why almost every car sold in over here in about the last 30 years has servo brakes. My Polo was an anachronism in that respect even when it was new.
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On a properly designed system, power brakes only provide reduced pedal effort. Like power steering, automatic transmissions, etc. it makes for less effort, not necessarily more safety. Power assist is just that, an assist. The pressure seen between the pad and rotor just requires more pressure from your foot. Again, if properly designed, it doesn't require an unsafe or impossible amount of effort. Just because you can lock up all four wheels with say 10 pounds of force on a power assisted brake system doesn't mean that a manual system requiring 20 pounds of force is unsafe, it just means the driver input required is different. I know my numbers aren't reality, it's just an example. It's more a case of driver preference. One of the reasons many racers use manual brakes is that there is more feedback from the pedal. I personally prefer the manual feel. I also don't have any difficulty exerting enough pressure on a manual brake pedal to lock up all four wheels instantly, so now the braking capacity becomes a matter of the friction of the tire contact patch and my ability to judge the maximum braking available from the car/brake system without locking up a single tire. This is the same capacity available if the car has power brakes, the only difference is driver effort input.
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I personally prefer the manual feel. I also don't have any difficulty exerting enough pressure on a manual brake pedal to lock up all four wheels instantly
I have to disagree with this. I may be a novice when it comes to cars, but this is the kind of question that comes up when talking about bikes all the time (the pedal variety).
You may be able to lock up all four wheels when driving along on a flat road, but when you're going down a steep hill there'll be more weight over the front wheels, so they will tend not to lock. Then you'll be straining on the pedal as hard as you can wondering why that hairpin bend/brick wall/tree is still coming towards you... I speak from experience (with cars this time).
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I wouldn't recommend going that way, imagine the insurance implications if you ever have an accident (even if the conversion is done correctly I can't see it ending well).
If manual brakes were all the jazz we'd probably use them on the C17 to save complication :) Instead we apply ~ 4000psi to 12 sets of massive brakes ;)
Take care and don't kill yourself!
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new cars also have paddle shifters and seats that auto adjust 14 different ways. is that necessary as well?
a couple important points: early rabbits came from the factory with non-assist brakes. going this route, its not as much a conversion as a retro-fit. also, the guys who seriously compete using the mkI body almost always have a non-assist brake setup (non-oem components, tilton MCs for example).
with proper hydraulic ratio there is no solid argument against non-assist brakes. its up to driver preference. they are less complicated and provide more driver feedback. the cost may be increased effort, but the resulting braking force, when setup properly, is the same or can even be better than a power-assist arrangement.
its about the hydraulic ratio. on a C17 is it possible to manually apply 4000psi to 12 sets of brakes by a single operator in a safe and easily-repeatable fashion? i have not operated a C17, but likely not. in a sub-2000lb tin-can of a car? all day long :mrgreen:
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If this swap is completed I want to see before and after panic stop videos from 60mph and the braking distances for each.
If Douglas decided to put a huge lever system in place....I don't think a human could provide enough power to stop an aircraft like that because of the volume of fluid required to be moved. Much of the braking is from the TR anyway.
I also wanted to note for the record, my czech status symbol 1987 Skoda 120GLS even had power assisted brakes...ahem...this should tell us something. That car was only 1968lbs and I was glad to have it. Power steering would have been nice as an option too when the "trunk" was fully loaded.
Screw it, let's all get horses. Back to the dark ages! No really, time for another beer and some drunken buggery. :lol:
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My Polo's brakes were crap. That's about all I can tell you with certainty :)
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wow.
non-assisted brakes aren't any worse performance wise than assisted - for light cars! the more mechanical advantage you need to build in with non-assisted, the more unrealistic the control job becomes - large pedal travel, etc.
there's plenty of a1 golfs getting around with non-assisted brakes, for rally and tarmac events - for all the reasons listed above.
however, something that noone has mentioned is that Joe Idiot, owner of motor vehicle, needs to be accounted for by motor vehicle manufacturer. Joe idiot doenst understand much about anything at all - so if he sees something in his way on the road - he slams on the brakes and swerves - which is why new cars have ESP and ABS, and over-assisted brakes - so that with one deft press of the pedal, Joe I is no longer in control - the cars ABS and ESP systems are doing his job for him, trying to stop the car in the least dangerous fashion they can.
For the discerning driver, who may be highly trained or well travelled, non-assisted brakes might be great - but for plebs, we have assisted brakes because its EASIER for us to apply the brakes without thinking too much.
Just look at the pedal effort required to use the brakes, compared with whether a vehicle is fitted with ABS or not - its pretty clear whats going on. more to the point - look at the brakes fitted to cars over time, against the advance of tyre/tire technology.
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If you ever drove a VW MK2 Polo, you would have had all the answers you ever needed. Excellent antilock braking system though, if you get what I mean, nope, no ABS. :shock:
MK2 Golf is 400lbs or so heavier, good luck. :wink:
My Polo's brakes were crap. That's about all I can tell you with certainty Smile
Amen!
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Is there any update to this. Did OP put on a manual system? If so what parts were used?
I am thinking about doing this because my power brakes only work when they want. I went through the entire vacuum system, even have a new MC on there and the booster checked fine. But if I dont slow down while in gear to keep the revs up I have no vacuum. The factory vacuum system is crap to say the least. Its probably a worn IM shaft, and I am not changing that.
I have looked at Wilwood and that other company but I would have to call them to see if they have anything that fits. Also does anyone know of where to get the proper booster delete. I seen some old threads on vortex (google search, not a member) where a guy was selling some he made. What about my pedal travel? Do I need to MK1 pedals, or will the MK2 work with the proper MC?
Will this work: http://www.jbugs.com/product/17-2808.html?Category_Code=vw-dual-circut-master
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Do you still have the old style diaphragm pump? If so that's your problem.
If you think for any reason that your vacuum pump isn't getting driven properly then you have bigger problems than brakes. The oil pump and vacuum pump share a drive gear, if the vacuum pump isn't turning then the oil pump isn't either.
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vanbcguy: I have the rotary vane pump. I rebuilt it and it benched fine. Interesting bit of info there. I didnt know they shared the same gear. I thought they were on the same IM shaft though. The gears looked good. But the shaft that turns the gears may be an issue. My oil light flashes and yells until the car is warmed up. Still I would prefer to put in a manual brake setup. If you have any info on doing that I am all ears.
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I agree with vanbcguy, check if the vaacum pump is in good condition. (Or just swap it) then check vaacum system again.
I have 4-5meters of hoses and connectors between pump and brakebooster, and yet when i checked the system still were under vaacum 3 weeks after the car is stopped, thats the way it should be.
But if you refuse to fix a good reliable system then go ahead, i have driven a Passat G60 Syncro with non-functional power brakes, no problem for me, Polo 86c as someone mentioned in this thread i was surpriced when i found out it was manual.
My guess is that the sceptics in this thread has had generally bad breaks and blame the no power assist part.
My friend needs power assist breaks, he also needs a cane for walking, healthy young men should have no problem locking 4 wheels of a 2ton van witout power brakes! As long as the rest of the system is in good order...
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The oil pump is driven off the vaacum pump, if you take out the vaacum pump you have no oil pressure...
If your oilpressure and vaacum is problematic at the same time it might be the pulley are slipping at the belt, tighten the belt a little?
The rotary vaacumpump also needs oilpressure to seal correctly, but it should not be a big problem... (because if you are that low on oil pressure the issue won't be stopping the car...)
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Renax: I already checked the vacuum pump and vacuum lines. I know that stuff is fine. Non-functional power brakes are drastically different than proper manual brakes.
The oil pump and vacuum pump it seems are driven off the same shaft or gear, perhaps someone can clarify that. But there is an IM shaft that drives them both which is driven by the belt. You can safely eliminate the vacuum pump and the oil pump works fine. If you ever check out a 8v you will see it has the same setup, but just a cover over the vacuum pump port.
My belt is fine, I check it on a regular basis.
I am well aware of the oil needed to seal the vacuum pump. Its not as low of oil volume as you might think. I can tell if my oil gets low by how the brakes react.
So if anyone can tell me what parts I will need that would be a great help.
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Renax: I already checked the vacuum pump and vacuum lines. I know that stuff is fine. Non-functional power brakes are drastically different than proper manual brakes.
The oil pump and vacuum pump it seems are driven off the same shaft or gear, perhaps someone can clarify that. But there is an IM shaft that drives them both which is driven by the belt. You can safely eliminate the vacuum pump and the oil pump works fine. If you ever check out a 8v you will see it has the same setup, but just a cover over the vacuum pump port.
My belt is fine, I check it on a regular basis.
I am well aware of the oil needed to seal the vacuum pump. Its not as low of oil volume as you might think. I can tell if my oil gets low by how the brakes react.
So if anyone can tell me what parts I will need that would be a great help.
You absolutely cannot remove the vacuum pump and have the oil pump turn. There is no gear on the oil pump shaft at all:
(http://img.auctiva.com/imgdata/7/2/8/3/3/2/webimg/655366601_tp.jpg)
The drive gear that mates with the IM shaft is on the vacuum pump:
(http://im1.shutterfly.com/media/47a3d727b3127ccef459508718a000000030O08AaNmrhi0buAe3nwQ/cC/f%3D0/ls%3D00008741856420130906170528585.JPG/ps%3D50/r%3D0/rx%3D550/ry%3D400/)
The tab on the oil pump shaft fits in to a slot on the bottom of the vacuum pump.
The 8V gas engines use a different intermediate shaft that spins the opposite direction and has the gear teeth cut on the opposite diagonal. They don't have a blockoff cover, they have a distributor sitting where the vacuum pump is on the diesels. The distributor drives the oil pump on the gassers just like the vacuum pump does on the diesels..
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vanbcguy: OK. Thanks for the education on that. I did not know it was so complicated. Thats that German engineering for ya. And the pics help.
So essentially I would just get rid of the vacuum lines for the brakes but still use the vac pump for heat controls. I still deem it a worthy endeavor.
And the question remains. Which MC do I put on and do I in fact have to change the pedal cluster? And what are the aftermarket options?
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Ignore the fact that you said you have rebuilt the pump and checked its functioning without knowing how it works.
Ignore the fact that if the vaacum pump, pipes and brakebooster is in good working order but this still doesn't work your engine has serious issues!
Even ignore that your buzzer of doom goes off confirming that your engine has serious issues.
In this thread the answers you seek already is written, complete brake setup from mk1 golf/rabbit/jetta without brake booster, or make your own setup (which is what i would do, because the mk1 system is a bit weak)
To put in a custom master brake cylinder is easy enough, just weld up a bracket to hold it and connect to brake pedal. Higher for better brakes, lower for worse...
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Renax: You can check a vacuum pump without knowing 100% that it drives the oil pump. Its really easy, you see, you just pull off the hose and put your thumb on it, or use a vacuum gauge (which I did).
What pipes? The brake booster could be the culprit. Or that stupid check valve. And the buzzer going off does not mean I have serious issues. I know for a fact I have good oil pressure. Its just how these old cars are, do some searching you will see.
After doing a bit more research and price checking it seems that trying to fix the antiquated system it has is the best option. I will replace the check valve and the booster. If this does not work, then I will rebuild the entire vacuum system. This is driven by price. And the fact that the guy who makes the adapters to put on a Wilwood MC will not reply to anything.
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You can check it, but you said.
I have the rotary vane pump. I rebuilt it and it benched fine.
But nevermind.
The buzzer going off means you have serious issues, thats what its there for!
"Its just how these old cars are" well, then i have to go fix mine, none of my 3 1.6 TD is setting of the buzzer, cold or hot.
There can be many reasons for the buzzer to go off, all worth your time fixing.
Even if its the system malfunctioning, because then you have no oil pressure warning...
I think that fixing the original system is the best option, but you know people have lives? the adapterguy might answer next week or next month.
If you want better brakes without vaacum get a ABS unit to hook up, my friend has a MK2 td with abs, then there also is a special lid with a gear instead of the vakumpump.
You don't need abs sensors, the powerbooster will work anyways:-)
This is also practical cause when your engine fails because of low oilpressure you can tow the car and still have power brakes:-)
(Yea, the last bit is tested, the rope snapped because i didn't think i had power breaks...)
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Renax: The buzzer does not mean I have serious issues. Its a common problem. Also my car has been checked over multiple times for this by one of the top VW performance shops in the US. So argue with them.
Sure people have lives. They are also connected by that nifty gadget often kept in the pocket. I like to call mine an LG G2. Some like to call theirs iPhones.
Do you have a link for this ABS thing? Since its not a hydroboost system nor is it vacuum. I would need to see pics of in order to determine exactly how it works. Because ABS by itself just creates a pulse. It has nothing to do with what force is used for the booster.
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"Its a common problem" well, yes, but having a flat tire is also a common problem, but the fact that its common doesn't mean it ain't a problem!
Many people has work phones and work mails not checked in the weekends...
Its not the abs part you want, its the electronic brakebooster that comes with it...
I don't have a link because i have never read anything of this online, just seen on some cars.
Its still a lot less work to just fix your existing system...
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To update, no, I did not ever go to manual brakes. At the time I asked it was a theoretical question and I was just curious about what was available for VW's. At this time I don't have any VW's so no current plans to explore this further.
As far as all the guys who said I wouldn't be able to stop the car in an emergency - you did notice that I have a 67 Ford Galaxie with manual brakes? I can pull it down from 100 mph no problem. I have a Fairmont with a 302 that has manual brakes. Works great and I really prefer the pedal feel. In my opinion power brake systems deaden the pedal feel. Just pulling the vacuum booster off is not what I was talking about. It's a system. Check out the Brembo racing brake catalogue http://www.brembo.com/it/Auto/Racing/Prodotti-Competizioni/Documents/CATALOGO_BREMBO_RACING.pdf (http://www.brembo.com/it/Auto/Racing/Prodotti-Competizioni/Documents/CATALOGO_BREMBO_RACING.pdf)- not a power booster to be found anywhere.
Absolutely, if there is a problem in your system, diagnose and fix it. I've driven vehicles with brakes that were OK in normal situations but eventually you'll get into one where you want brakes at their best. Building a better braking system is always good, but just keep in mind that no matter what the brakes can handle, they can't do anything more than what those 4 little patches of rubber that contact the road can handle.
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Renax: Like I said I have had one of the best VW tuning shops in the US check it out. They did every test and changed out the sensors, dug into the engine and the whole nine. And you know what they found? Nothing. No low pressure, properly working sensors, etc. The only thing that it could be is the cluster panel. And that is not a serious issue by any means.
I will be replacing the check valve and the booster first. That will probably do the trick. If not then I go to other measures.
clbanman: Thanks for following up.
I have had cars including a 71' Cuda with manual brakes that stopped great. I know its a system, and you cant just use any MC for it, it has to be designed for it.
Also I have some pretty good rubber patches.
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Check out the info at http://www.gowesty.com/library_article.php?id=810 (http://www.gowesty.com/library_article.php?id=810).
It's for a Westy, but I assume the logic is the same for all VW's??? Seems to explain the problem you're having.
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Excellent article. I am going to check out or replace the wiring.
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Solved the hard brakes problem. Had 2 small oil leaks and when it gets low on oil as we all know the vacuum pump suffers. Fixed the leaks, now just have to wait till morning to make sure its full and brakes will be working great.
I replaced the low side oil pressure sensor, but this did not fix the annoying buzzer. Still have to do the wiring.
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I guess I didnt totally solve it. Initial braking is fine. But the 2nd pump is stiff. I am getting plenty of oil. I will replace the check valve, check the vacuum pump again, and have the booster checked over. Could be that the booster has fluid in it.
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I guess I didnt totally solve it. Initial braking is fine. But the 2nd pump is stiff. I am getting plenty of oil. I will replace the check valve, check the vacuum pump again, and have the booster checked over. Could be that the booster has fluid in it.
Did you try T in a vacuum gauge and observe vacuum levels while you drive?
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That tee and a gauge is the way I would go. When you get cars this old, one possibility would be a crack in the booster diaphragm that allows vacuum to build and hold when the pedal is not applied, but then as you apply it, the leak starts. One possibility why the first application is powered but the second is not.
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92: I do not have the equipment to do that right now. I will look into it though.
clbanman: I am going to replace that check valve and probably the brake booster at some point.
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Put on bigger brakes, (g60/gti/vr6) and you can use the old brake master without powerbooster. The bigger brakes has a larger cylinder, which means that with the small cylinder master you will get the wanted effect. :-)
Big brakes with powerboosted small master will feel squishy...
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I'm pretty much as big as I can go. Any bigger and I would need larger rims. And larger rims won't fit without issue.
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I've had 9x16" et15 rims on my Golf, would fit on any mk2:-)
7.5x17" et37 fits also... without issue other than looks...
6x15" et35 is original G60 rims, will fit over G60 brakes and not look like a donk:-)
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Perhaps I will fix what is wrong first. Then go to braided stainless steel lines, then eventually the bigger brakes.