changing MK1 Caddy to Mk 2 master cylinder

[Blue Haze]

I understand this is a good upgrade but don't what's involved.  Currently my Bendix mk1 unit leaks at the reservior gromments and I cannot get it stopped.  I'm considering this upgrade I assume I need master cylinder, servo, will the brake lines from the proportioning valve to the master cylinder fit or do I need the lines from the MK2.  Will the existing pedel mate up to the servo?  Any advice greatly appreciated

[mystery3]

What year is your car? I've never heard of anyone upgrading to the mkII unit but I think it maybe due to the amount of work and limited gains. I think the brake lines enter the mc at different angles and such and must be replaced other than that I'm unsure.

[8v-of-fury]

Have you upgraded the rest of the braking system? Bigger pistons up front? discs out back?

Not really any need if it is only being replaced for leaks. An OEM mk1 will do you just fine.

I do agree I think mk2 is different line angles, but aren't they the same size bore as the mk1 stuff??

[CRSMP5]

too much work for minimal gain...

upgrade to german pedals, booster, master and no more westy crap master issue..

at this point a 16v rocco booster/master is a bolt in upgrade..

[mystery3]

aren't they the same size bore as the mk1 stuff??

They are as far as I know but the lines on my truck were original and I don't think the likelihood of getting a clean bend on a 30 year old brake line would have been too high. Perhaps if the hardlines had been replaced relatively recently it could be done?

[mystery3]

I also don't think the mc is the weak link in the braking system of the mkI. Do you do a lot of hauling or race? I think a new/reman'd ate mc with big discs up front, a rear disc conversion and nice pads, I like hawk HPS, should do well.

[8v-of-fury]

Very true, but if you go big pistons up front and discs out back you will more than likely need a larger MC to push enough fluid.

I do just fine with my M-tdi.. I have the cheapest brake shoes and pads I could purchase. 180x30 drums in the back and solid 9.4's up front.

[CRSMP5]

well see this is where you fail..

i know its been discussed how i have 84 coupe with 10.1" fronts, 4kq bolt on like 16v, rear disks.. stock master/booster, breaks are a tad lower, but braking force is better then 16v rocco.. i can lock all 4 up with less effort then mulit 16v roccos i drove at work..

toaster has 200mm rear drumb... 11" fronts on westy booster/pedals/master.. had same issue op has.. the only reason i did not go german once it happened is all the mod time i had in the westy pedals.. modded for grumman and hydro.. but after a year or close to it it stopped leaking... after 4 tries of masters i got the one that leaked dry in a mo.. then winter hit.. sat warm inside.. took out in spring.. empty daily then after 2 gal not a drip..

my only cure is german parts.. westy master is a issue.. and its due to the redesign/how the grommet area of master is differen tthen original design.. went from nickle dimeter bushing to quarter sized.. so now the rubber is too thick to seal up when bottle put in..

[JamesT]

Now that everyone has told you not to, I'll give you a helpful post.

I have a mk3 master (nearly identical to mk2) on my caddy.

To do this, I used the mk3 brake booster, mk1 brake booster, mk3 master cylinder, 2" of 7/16" ID pipe drilled out to 12mm, and new hard lines.
I carefully measured from the mounting face to the eye of the mk1 actuator (the part that attaches to the brake pedal). I cut the mk1 rod off at an arbitrary distance that would not interfere with the actuation. Next, I marked where on the mk3 rod would make the same distance and cut it off there. I ground the booster's actuator rod and the cut off piece of mk1 booster to a taper, slid the pipe over the booster's rod, and then I welded the two tapered ends together. I filed the weld flat to the rod and slid the pipe over the weld. I welded both ends of the pipe to the rod. Finally, I mounted everything in the car, and installed new hard-lines.

A mk2 booster may just need a different end threaded on (I haven't measured), but the mk3 had a stupid ball thing on the end.  The important thing is that you use the later booster as the mk1 master doesn't sit as far into the vacuum can as the mk2/3.

A few advantages to doing this:
-It takes up far less space than the stock mk1 setup.
-The booster is newer and easier to find in good condition.
-Choice of 20.0mm or 22.2mm master cylinder
-No downward facing brake lines.
-Better styles of fluid bottles available.

I did it because I had the parts sitting there. My brakes are fantastic, and I don't even have good vacuum running to the booster.

[madrogers]

nice to hear that R&D project worked well, its thinking outside the box that will keep old cars on the road, our provincal auto insurer is shreding ever pre 95 car it can get its hands on , just to dry up the parts for the rest of us that dont want to buy a new one and pay the top rate on insurance to them.

[8v-of-fury]

Or the people who just don't want the headaches of replacing your car every 70k kms?

Brothers shop sees 2009 cars with under 80,000 kilometers on them that have rear main leaks.. cam shaft issues.... engine knocking?!?

Gosh darn ridiculous.

[JamesT]

Update on my brakes: Fantastic.

I now have a good strong vacuum pump in the car, and the brakes feel like a brand-new car.  Unfortunately, this means they are completely without feel, and a couple times I've locked them up because I was used to the pressure it used to need to apply the brakes.  I'll post some pics of my MC when it stops raining.