MASTER CYLINDERS / POWER BOOSTERS / ETC.

LATE MODEL MASTER CYLINDER SWAP

Ok, you don't feel like running that old school metal master cylinder and want to do something different. I agree that the early master cylinder is a heavy eyesore and the piece of crap just rusts and leaks paint eating brake fluid all over your detailed engine compartment. Time to chuck it out and go modern.

You can replace it with a late model master cylinder from pretty much any a 1979 to 1989 vehicle. I have seen plenty in diplomats and the like at the salvage yard sporting this unit. It is also sold new by mopar in two different bore sizes, 15/16" and 1 1/32", which provide different pedal "feel". This master cylinder has plastic screw top fluid reservoirs and a light weight aluminum body. I personally have not seen the 1 1/32" in aluminum at the salvage yard I think it only came cast iron OEM. The big bore iron models are usually found in trucks.

SPECIAL NOTE HERE: If you decide you want an aluminum master cylinder you can find the 15/16" unit rebuilt at Autozone, for like $14.95. They also sell a new one with plastic reservoirs for $49.00. I found my iron truck 1 1/32" unit at Autozone rebuilt for the same price. Additional information is provided below.

If you want a big bore 1 1/32" ALUMINUM master cylinder you will have to buy Mopar Performance piece (PN# P5249271 $159.25 List price, the 15/16" is PN# P5249270 $111.75 List price). Again the big bore, best to my knowledge, never came in aluminum as OEM. The 1 1/32" IRON rebuilt I bought at Autozone (PN# 10-1860) is rebuilt by "Fenco" (don't know who they are but piece looks excellent). The application was for a 1979 Dodge D100 truck 2WD. It cost $14.95 and does NOT have the plastic reservoirs included which is the same deal with the smaller 15/16" version. So don't toss old the old plastic reservoirs from your core as they are reusable with some cleaning. When I was scrounging around in the yard I pulled the best condition plastic reservoirs I could find and didn't even bother unbolting the rest of the MC as Autozone only charges $10.00 for cores. In the long run it's cheaper and easier than pulling some core and having the yard guy charge you $5.00 for it.

Unfortunately all newer master cylinders use a two bolt mounting system rather than the early four bolt setup. What to do.....

Mopar Performance has come to the rescue (sorta) with a adaptor plate that will ease the pain of installing this late model master cylinder in your early ride. It is part number P5249315 and costs about $35.00. Like mother Mopar she isn't doing you any favors either. Much like the 360 flywheel and this adaptor plate, once Mopar is producing a part they remove any reference or blueprints on how to make it yourself from the newer chassis manuals.
If you are new to the hobby you must be going "what the hell is he talking about?"

For example, I needed a 360 flywheel. Those on moparts board told me to just look in the chassis manual and it tells you how to drill a 318 flywheel to work. Hmmm so I happily go down to my local Chrysler dealer plunk down 20 bucks or so and buy a chassis manual. And you know what.... nothing can be found.
So I go back on the board bitching and whining that it was not in the book and kept hearing that it was in the earlier editions. I then borrowed an early 1980's chassis manual and there it was...tons of info how to make a 360 flywheel and the diagrams for making an MC adaptor plate out of flat aluminum stock.

I find it very insulting that this information was omitted especially if one considers that maybe not all mopar enthusiasts can afford the new mopar part or just want to make it themselves to save money. There is no other reason possible that these illustrations were removed except that mopar began producing these pieces and didn't want to lose revenue from those who would make the parts themselves.
To add insult to injury the rest of the book hasn't been rewritten in a decade so the only revision was to remove income robbing illustrations.

This just illustrates that MOPAR INC. is not your friend they are in it for the money which is fine to some extent. I believe in a capitalist society and things should be produced for a profit. I just don't believe that too many people will go and drill a 318 plate as you need big 1 1/8" drill bits and accurate machining to produce a good part. This is beyond the scope of most people, however a select few will build it. I don't believe that these "do it yourself" people will adversely effect the gross sales of Mopar Performance pieces. It would be best for Damiler Chrysler to help out the Mopar guy and forget this penny pinching stuff as a happy Mopar Performance consumer may go buy a new Durango or something where the real $$$ is made for the company.

Anyway, enough bitching, I digress.... in the current 2000 MP catalog MP also wants you to plunk down another $63.00 bucks for an adjustable brake push rod (PN# P5249316). However, the old power booster one works fine in a stock POWER setup as it is ADJUSTABLE! IF you don't have power-braked car just bend over grab your ankles and cough up that $63 for the adjustable rod that must cost like $3.00 to make.

After installing the plate measure the depth of the hole in the master cylinder verses your old one and adjust the rod for any difference in length from the plate's installation.

Time to hack on Mopar Performance again. I bought their plate I must tell you I wasn't satisfied with it. There is a lot of bitching going on most web boards about MP's quality and this plate is a reflection of that. I got the plate and was all excited until I installed the studs. Well they were not drilled and tapped 90 degrees verses the plate but like 80 and 85 degrees, a picture of this is further below. In addition, the studs were loose in the threads. Defective plate or crappy quality?

Now with the misaligned studs I couldn't install the MC as it wouldn't slide down them. Nor did I want to use this plate as I don't want to risk my life or kill anyone else if these studs rip out and cause an accident. Mopar Muscle in their July 1999 issue (Page 82) did a job on one of these plates where they countersunk 45 degree grade 8 bolts through it as they had the same concerns of safety. I was going to do the same with this junk MP piece until a better alternative came to me about a week ago.

GregZ on the moparts board sent me a prototype plate that he will be producing in limited quantity this year to see what I thought of it. It is an identical plate to Mopars but a little bit thicker, not black, and will incorporate the grade 8 countersunk bolts just like Mopar Muscle did in their article. Now the plate I am showing below is a prototype and uses screwed in studs, Greg sent me the grade 8 bolts to replace them, and all later plates will be of the countersunk bolt type.

Time for a disclaimer: I am not making money on this product, know GregZ any more than anyone else on the Moparts board, or accept any liability if you choose his product over MP. I like Greg's product and the reason I am putting his piece on my site is to just to let you, the mopar enthusiast, know about an alternative in the market place. From what I am told he will sell it for less than the MP unit. Better product, cheaper the price..how can you go wrong?

The following pictures tell the tale better than words can.

In this picture you can see the MP plate and Gregz's. They are identical. MP's bracket had a slight countersinking of the old 4 bolt MC holes. Nice touch but this isn't an engine block deck so who cares, anyway those holes will be countersunk for those grade 8 bolts. MP's is anodized black too which is cooler than Greg's but to me it doesn't matter as I am painting the whole booster / plate / MC when it is assembled.

Here are the two plates side by side. Greg's piece was a lot thicker and while I felt that thicker is definitely stronger it raised concerns initially if the stock MC booster rod will adjust to compensate for the additional thickness. Well it did just fine and should also be with the $63.00 MP non-power rod too. I don't know if later versions of Greg's plate will be thinner as some people may not like the additional thickness.

Now take a close look at the two studs. The MP stud is not drilled properly, it isn't 90 degress like it should be. The crappy machining of their plate really annoys me in this TQM era (total quality management). This is inexcusable. Greg's is a nice 90 degrees with nice tight threads. Again the later versions will have those bolts rather than studs but Greg did a nice job building this piece.

Here is a picture with the mopar inner boot installed. This part is about $7.50 and available from Mopar (PN# 5204051). The plate needs to be opened up just a little bit, about 1/32", to allow this seal to be installed as the rubber is too thick. Or you can grind down the outer diameter of the MC a little which is easier. The MC I am using is a big bore iron truck unit. This too tight situation waas the same with the Mopar produced plate, so I think my MC may just be a bit too thick.

Here is the whole deal mock assembled without the inner seal (haven't found the time to open up the inner bore and make it fit). The MC fits snugly in the plate bore with no seal as it should and everything looks and fits fine. Overall a nice product.

If you want to buy a plate GregZ's email is: ZSCAMP@aol.com

POWER BOOSTER SWAP 73 -76 A BODY TO 67 - 69 A BODY

If you want to run power brakes on your A body (which doesn't need them) 73 - 76 power brake booster fits in place of the older 67 - 69 Cuda units.
After I did the big brake swap on my 68 convertible and put the 73 - 76 master cylinder on my old booster the @%$# booster was leaking vacuum (engine rpm would jump up and down when I hit the brakes). It was junk. Not wanting to pay up for a rebuilt 68 unit I went to Autozone and bought a 73 - 76 rebuilt booster. The diameter of the later booster is larger than the 68 and I had concerns that the hood wouldn't close especially since my rebuilt had the canister clamping bolt on the TOP of the unit making it ½" higher still. I couldn't loosen it as the factory bent over the clamping bolt to discourage internal tampering.
It fits perfectly (small block engine) and I have had no problems with it. Here is an old picture of my car before I pulled the whole unit out to repaint it and add Gregz's MC plate adaptor along with the newer MC.

Now if you want to stay old tech and run the old style 4 bolt master cylinder, Autozone sells rebuilt master cylinders for $18.99 and rebuilt power boosters for $89.95. If you buy the whole assembly together its $99.95 with a lifetime warranty. No better deal out there.

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