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Need Help! Rear Disc brake upgrade -1980 Caddy
by
Familydiesel
on 13 Oct, 2008 12:42
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I want to upgrade the rear brakes on my 1980 Caddy to rear disc brakes. I have an opportunity to buy a donor car (1985, GTI Golf). This has rear disc brakes.
Will these brakes bolt on to my current Caddy? I have read in the PartsPlace catelog that 86-92 GTI rear discs will bolt up to the older cars. So, will the 85 GTI Golf disc assemblies bolt up? Will all GTI's bolt up or just the Rabbit GTI's etc?
Also, are the front discs on the 85 GTI larger than the stock 9" I have? Will these bolt up as well?
I need better braking since I am also installing a 1.6 td and will be using the Caddy as a daily driver along with pulling a trailer behind it.
I would appreciate any counsel and information about this.
I need to make a decision soon whether to purchase this Golf GTI or not, based on whether the parts will fit.
One more thing: This will probably sound stupid to many, but I don't quite have a handle on the terminology yet. What do the Mk1, Mk2, Mk3, Mk4, Mk5 refer to? Different body styles models, and years? For example is the Caddy I own a Mk1? What years do these terms refer to?
Thanks,
Greg
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#1
by
rabbitman
on 13 Oct, 2008 15:42
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Not sure if the rear discs work on a caddy. The front GTI discs might be vented and would be a good upgrade, you'd need GTI pads which are thinner because the vented discs are thicker.
Mk1 goes from 75?-84
Mk2 goes from 85-93?
Mk3 goes from 93?-98?
Mk4 goes from 99?-2004
Mk5 goes from 2005-?
As you can see I don't know exact myself, but I don't care very bad about anything but mk1. :lol:
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#2
by
foxracer1
on 15 Oct, 2008 10:13
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The rear disc will fit. All rear disc are interchangeable all the way up to MK5 with the exception of the bolt patterns on the disc. Aluminum rear disc calipers from a MK4 will bolt up. The front brakes are more complicated. Look on
www.vwvortex.com for an indepth write up.
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#3
by
Familydiesel
on 15 Oct, 2008 11:52
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Thanks for the input. This is helpful. Does anyone know if this 85 GTI Golf has bigger brakes than my stock 9" on the 80 pu, or are they possibly vented, but not bigger?
Thanks again for the input.
Greg
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#4
by
jtanguay
on 15 Oct, 2008 12:07
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don't forget that you need the parking brake cable from a disc setup as well...
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#5
by
Familydiesel
on 15 Oct, 2008 12:09
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Yes, thanks for the reminder. Do I also need the brake proportioning valve?
Thanks,
Greg
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#6
by
AudiVWguy
on 20 Oct, 2008 22:45
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P-valves are recommended. After install, wet the road really well drive and hit the brakes till they lock up. If the rears lock before the fronts on the wet surface thats bad. You will need the P-valves to be braking safely.
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#7
by
Quantum TD
on 21 Oct, 2008 00:25
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I believe that the 85 GTI uses mere 9-inch brakes like earlier cars. Only the 16V GTIs (of 1989-up) had the larger 10.1 inch brakes and Girling Calipers. These later calipers are what were used on the MK III cars as standard issue. Before that, only the 16V GTI, GLI and Scirocco had them.
But, as noted by others, the fronts are vented. Frankly, I've often found the solid rotors to brake better and be less prone to warping. But, that's just me. You may want to convert. BUT, there could be a problem there: the brake pad carriers on the 1985 are part of the spindle housing. You'd have to swap the spindles onto your Caddy. I can't remember if this is possible. I'm pretty sure the struts won't fit over the top of the spindle, and I think the lower ball joint is different size too. So, you may be SOL on the front brakes.
If you want to upgrade your fronts, I think you only bet would be to find some 16V Scirocco front calipers and carriers (hard to find these days). They will bolt right up to your front spindles, and they are 10.1 inch vented style Girling Calipers. While the calipers are all the same for 1989-up 16V cars and MKIII cars, only the Scirocco had the carriers that would bolt up to the MK 1 spindle. Contrary to popular belief, the other 16V and MKIII carriers will not.
The rear calipers will bolt right up. You'll need the stub axles and the backing plates to bolt them up to your rear axle. I do forsee a potential issue with the E-brake cables. Check the poortex. I'm sure someone has figured out a solution. Normally, you'd use Scirocco 16V cables on a Rabbit, but the truck cables are longer.
Also: the 1985-1988 rear calipers had the e-brake cable mounted to the TOP of the caliper. Later cars (1989-up) switched them to the bottom. I used to live in New England, and the early style ones were quite prone to siezure due to the fact that salty water would dribble down the e-brake shaft to the heart of the caliper. The caliper might work the brakes, but the E-brake part would do nothing. If you live in a road-salt zone or a rust zone, it may be a better idea to get some rear calipers off of a later car, and use the stub axles off this car (I may be wrong on this: thinking they interchange). Anyway, something to think about.
As for proportioning valve. Your truck should have one mounted to the rear axle, or just the simple one mounted in the engine bay. If you have the rear-axle style, then you may be able to adjust it (can't recall if it's adjustable: and I think only the 1980 truck had the axle-mounted one). If not, then 16v proportioning valves are a good idea.
Good luck!
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#8
by
VWCaddy
on 22 Oct, 2008 09:13
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Not sure if the rear discs work on a caddy. The front GTI discs might be vented and would be a good upgrade, you'd need GTI pads which are thinner because the vented discs are thicker.
Mk1 goes from 75?-84
Mk2 goes from 85-93?
Mk3 goes from 93?-98?
Mk4 goes from 99?-2004
Mk5 goes from 2005-?
As you can see I don't know exact myself, but I don't care very bad about anything but mk1. :lol:
I have a collection of chassis codes vs. model years on the web page below:
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http://www.4crawler.com/Diesel/ForSale/ChassisCode.txt
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#9
by
GEE-BEE
on 01 Jul, 2009 12:09
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[email protected] makes longer ebrake cables for rear disc conversion
He also makes adapters for G60 calipers on stock mk1 spindles
You can use 16 v disc and you will need spindles and PP valves for the rear, unless you find a Corrado donor car like I did and took the seats and brakes...
22.5 ( 16 V )Master cylinder and MkII brake pedal assy if you dont want to weld
I did new master cylinder and Booster, MK11 peadal assy ( 16V ) Scirocco
G60 brakes / Disc's ( Huge )
Weitec Coilovers front , Axle flip with airshocks rear
Front & rear sway bar set with Upper Strut bar
Everything Just bolted on
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#10
by
Familydiesel
on 10 Jul, 2009 12:28
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Thanks for all the info. My 80 Caddy does have an axle mounted rear proportioning valve. I will check to see if it is adjustable and give it a try.
I also have the rear prop. valve from my donor 85 GTI (8V). I am looking to add sway bars and the tower support bar. One thread showed a bottom support that bolted to the side engine mount and to the side frames. This was supposed to beef up the bottom front considerably. It looked like a frame for a rear trailer hitch. Anyone install one or something like it? Does it make that much difference? I like bolt on upgrades!
I hope to start working on the caddy again. Right now it is sitting on ramps without an engine and transmission. I resealed the tranny, and rebuilt a 1.6 td and put a Garrett t2 turbo on it. I also have a front intercooler waiting to be modified and installed with the engine and tranny. Then, I will need to plumb in an air oil cooler, in addition to the stock water/oil cooler.
I need to take the motor to the local hydraulic hose shop to get a drain hose made. We don't have anyone local shops that seem to carry a good supply of metric pipe fittings, so I am stuck with getting a hose built.
I have been too busy
to spend time cleaning and painting the engine compartment, assembling a new front end, and then installing and plumbing in the engine. Thanks for the great input.
Gee Bee thanks for the tip on the rear cable supplier.
Greg
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#11
by
burn_your_money
on 11 Jul, 2009 08:49
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Do you guys get snow in WA? How about salt? VW's rear calipers are pretty crappy and have a tendency of seizing the e-brake cable (from what I've read). You already have the larger 200mm rear drums, and if you wanted to you could go even bigger with the passat B3 B4 rear drums. I think they are around 230mm. Put electric brakes on the trailer if you are really worried.
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#12
by
Familydiesel
on 11 Jul, 2009 13:43
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Hey VWCaddy,
Thanks for the clarification of body types. Good work.
Tyler, we do get snow, but not much. We live in the desert of WA and don't have much precipitation. We do get most of our moisture from Oct.-March.
I have also read some about the e-cable problems and take it to heart. Would the larger drums stop the caddy as well as the rear disc? I have an 2004 Impala with rear disc brakes and they stop nice, as compared to our smaller 97 Grand Am with drum brakes. I'm not a brake expert, but have been envisioning disc being better than drum; though larger drums could provide better sopping in the rear.
I do plan to put electric brakes on the trailer, especially since I have been pulling it with our Suburban and it labors under the weight. It is only a 5.8 tool trailer, but is probably pushing 2000 lbs.
Thanks for the help,
Greg