Hard to find master cylinder!

[MarkV]

So, I can find parts for almost every single one of my cars! Well my friend has a 1986 Oldsmobile 98 Regency Brougham and the master cylinder is going out. Anyway, I thought it would be an easy swap with a new one. Until I found out it has some kind of early ABS! No one has the master people are afraid to touch the existing one in fear of not being able to find the parts to fix it! I need help finding this thing! It has a sensor and float on/in the tank, and that is one of the main issues, in finding one. It is unbelievable that when I can still find the parts for my other cars this one cannot be found! Help would be much appreciated!

[Guest Jim_Edwards]

The "IDIOT" ABS system in that car is a TEVES Mark 2, 4 wheel integral system. The original design was done by ITT circa 1984 and sold to TEVES of Germany in 1987. The particular type was used on Oldsmobiles from 1986 through 1990.

The same system basic system was used on Lincoln Mark VIIs and costs more to repair, if one can find the parts, than the car is worth. The system in my '87 Lincoln Mark VII has issues and I have arrived at the conclusion the only way to get around it is to pull the entire system and replace with a conventional system with no ABS.

FYI this is a link to a list of cars that have that stupid system and it might just be possible to find a good master cylinder from a salvage yard that still works. Not sure what will interchange, but a number of GM produced vehicles used that dog of a system. ANTILOCK BRAKE SYSTEM (ABS) SYSTEM APPLICATION CHART

There were Oldsmobile 98s produced in '86 that were non ABS and the easy and cheapest thing to do may be to convert to that system.

[NTX5467]

Many master cylinders had level sensors in the master cylinder reservoir. BUT . . . what you most probably have is the . . . . (drum roll! funeral march next!!) "PowerMaster" power brake booster.

In this booster, which is much taller than it's wide, it all comes as a unit . . . master cylinder and booster because they all work together as a unit. If you've driven his car, you probably noticed that it isn't the most powerful car on the street, even when it was new, with the Olds 307 V-8 in it. As a result, generally lower intake manifold vacuum levels, I suspect. So, less vacuum to run the power brakes with a vacuum booster setup. Some of those Olds' had an auxiliary vacuum pump run by a V-belt, too!

What happens is that when the car is started, an electric pump pumps fluid from the master cylinder into an accumulator below the cylinder (the small balloon-looking item which screws into the main housing). When the pump works, you can visibly see the level in the master cylinder decrease, which is normal, but still somewhat unnerving, generating "When do I check the fluid level, when 'off' or 'on'?" In some cases, the master cylinder reservoir would seem to almost be "bone dry" after the pump started working!

When the cars were still newer, GM sold a new unit for it. Later, it became a "GM Reman" unit only. Later still, they had a bulletin about having to call a lawyer's office to order a reman unit. Eventually, it was all discontinued. Every car with one of them from the factory, which was in a salvage yard, back then, had the booster missing from it.

This booster was also used on the Buick GN turbo cars (another low/no-vacuum situation engine, especially under boost). You can probably find some threads in the Buick GN-oriented forums about retro-fitting either a GM Hydro-Boost unit (uses fluid pressure from the power steering pump to run the booster, as on GM diesel cars and pickups from back then, but will probably require some "rigging" to get the factory-configured set-up to work in your chassis, many power steering/hydrualic lines.

But it seems like the GN Turbo guys had another, GM production, power booster setup they came up with to replace the PowerMaster with. GM part numbers and applications/vehicles which had the desired parts on them are in their Instruction Sheet, as I recall. With that instruction sheet, you can probably cross them into new or reman parts from the auto supply vendors.

The PowerMaster was an interesting way to do things. A way that was not dependent upon the engine for its vacuum source, but used electic pumps and such instead. Were it not for the seeming complexity of power steering hoses for the Hydro-Boost system, I'd recommend converting to that system (power steering pump, booster, lines), but you'd need to find a similar car that had the GM 5.7L diesel from the factory (Caprice/LeSabre/Bonneville/Delta 88).

The ABS system on the car, if equipped, is a totally separate situation. With its own servo motors to control brake fluid pressure to the respective wheels.

So, check to see what the Buick GN Turbo operatives might recommend replacing the PowerMaster master cylinder system with. Proceed at your own risk.

Enjoy!

NTX5467

[Guest Jim_Edwards]

You forgot to mention the failure of the accumulator, as did I. When A1-Cardone won't touch the rebuilding of one you know it's a bear to deal with. Accumulator failure can give one somewhat the same impression at the pedal as a blown master cylinder, but the issue is no boost.

[Rawja]

If the unit we're talking about looks like the photo below I'd strongly suggest posting your symptoms down in the Buick Reatta Forum where our resident experts can walk you through diagnosis.

Parts are still available, remans have been and continue to be available. The system is sensitive to neglect, but properly maintained is very reliable.

Most mechanics simply don't understand the system, though it's fairly simple and easy to repair as there are a few very easily replaceable items that "go bad": Power relays, pressure switch, pump and the accumulator.

Even if you end up taking it to a mechanic, do the diagnosis yourself as they will generally just throw parts at it, unless you track down a garage that specializes in 80's European makes many of which used this system.

[joe_padavano]

In this booster, which is much taller than it's wide, it all comes as a unit . . . master cylinder and booster because they all work together as a unit. If you've driven his car, you probably noticed that it isn't the most powerful car on the street, even when it was new, with the Olds 307 V-8 in it. As a result, generally lower intake manifold vacuum levels, I suspect. So, less vacuum to run the power brakes with a vacuum booster setup. Some of those Olds' had an auxiliary vacuum pump run by a V-belt, too!

Better go read his original post again. He's got a 1986 Olds 98, which is FWD with the transverse Buick V6.

[NTX5467]

I did go back to double-check the model year, but I also know we had Caprices with that system, too, which is where I was (at Chevy parts) at that time (with no H/C fwd platforms). We later got Olds, which was then swapped for Buick, in the later '80s, which was my first real parts exposure to the upper-line GM fwd cars. Most of what we saw on Reattas were issues with the anti-lock systems as they aged, not the boosters.

On the dealership side of things, if GM doesn't service it any more, it's gone. Unless somebody "pushes", there's no real orientation to seek information from outside sources, especially when the shop has to warranty any repairs they do for a certain period of time. Especially in an area where they have little experience or don't want to go.

When we'd get a Reatta in with anti-lock issues, and GM not having any listings any more, or greatly-elevated prices, I'd get with the service advisor and tell them how things were (from GM), and then offer them Barney's email contact information to give to the customer. One already had his information in the glove box!

I'm glad to know the system's parts and pieces can be obtained.

As for the accumulator issue, how much different is that accumulator than what's on the Hydro-Boost unit? Can the Hydro-Boost accumulator be adapted? Just curious.

Take care,

NTX5467

[Rawja]

Here's the accumulator..

Amazon.com: ACDelco 25528382 Pressure Accumulator: Automotive

[NTX5467]

Thanks for that link! An interesting page!

Thanks!

NTX5467

[MarkV]

Whats funny is that it looks nothing like that unit. I think someone made a mistake thinking it was ABS when it is not. I found a master that looks just like the one in the car with the sensor. I may have to cut the sensor wires and adapt a different plug, has anyone done this? As the plug on the existing master looks different....