Brake System

Can any one tell me if the system used on the first three years is the same as what the Allante used up until 1993 ? It's physically somewhat different.......but is that it ?

I don't know what the Allante used but there is no indication they are the same manufacturer.

The Allante has a Bosch label. They called the Reatta a Teeves, right ? I guess I was wondering if a Teeves is a Bosch system ?

No. Teves was one supplier (Alfred Teves) of integrated ABS systems, Bosch was another. The Teves Mk II system fitted on the 88-90 Reatta and many other cars (GM and otherwise)in that same era is a completely different design from any of the systems Bosch offered.

GM largely transisitioned to Bosch supplied ABS systems starting in 1991 model year vehicles. Essentially there is nothing interchangeable between Teves and Bosch hardware. I don't know if the pre-1991 Allante had Teves or not, but have to figure 1991-93 was Bosch.

KDirk

Early Allante's had the Bosch system.

Thank all of you for your input. From what little of read, so far, the Allante used the Bosch in the first year through 1992 and dropped it in the last year. I've read blogs/posts from people who have owned these and have had them all of sudden fail with no warning, if true very scary. I got to thinking about the Reatta's and wondered if needed the have concern about mine ? I've seen or heard any one talk about this happening and quite honestly maybe the Teves design will give some braking should the unit fail (minus any lines or hoses breaking of course).

The Teves Mk II system on the 88-90 Reatta is reliable and proven. That said, it's design is unique in that it requires very high pressurization and must use a pump and reserve pressure vessel known as an accumulator to maintain the needed pressure for the brakes to function.

Thus, a failure of the pump (relatively uncommon), the pump relay (also fairly uncommon), the pressure switch (somewhat common now due to age) and/or the accumulator (increasingly common from age now) will cause loss of pressure and in turn of braking function.

This can be very disconcerting, as a loss of pressure at the pump/accumulator will cause "hard pedal" and leave you with virtually no brakes. It can and does happen spontaneously on any failure of the components above.

Now, proper maintenance and proactive maintenance are your best bets against this happening. Flush and replace brake fluid bi-annually and perform the functional test to verify pump, sensor and accumulator performance periodically. Replace parts that are marginal.

Better still - though it is admittedly expensive - replace the accumulator, pressure switch and pump relay on a preventive basis to be sure you won't be caught short. After all, these parts, if still factory original, are at least 24 years old now (for 1990 models) and I'd say that is a more than respectable service record for safety critical components. Point being, I wouldn't feel too bad about chucking brake system parts that are that old, even if still working if you really want maximum peace of mind.

Now, I still have original parts (relay, pressure switch and accumulator) on my 88's, but have new spares on hand for both cars. If going on a long drive (i.e., out of town) I bring the spares and tools to install them with me. Just a necessary precaution on cars that are a quarter century old. On short jaunts around town I take my chances knowing I have the parts at home.

Granted, I am tempting fate by stretching the service life of old parts this way, but on my cars they still work and show no early signs of failure or even reduced performance. There is no way to predict a sudden catastrophic failure, so therein lies the biggest risk. YMMV.

KDirk

Kirk

What does "virtually no brakes" mean ? Does it reduce it to a simple old hydraulic (no vacuum assist or in this case hydraulic pump assist) type setting/feel ? I hope I'm not seeming paranoid (I'm not), I'm just curious as to how serious of a situation this really could be.

On the Teves system, loss of pressure (due to any of the failures outlined in my previous post) causes loss of standard braking as well as the ABS functionality. In other words, you won't just lose anti-lock with a "downgrade" to conventional brakes. This is because the Teves system does not employ a standard hydraulic braking system with ABS "grafted on" as with many systems (like the Bosch setup used in the 91 Reatta).

Rather, Teves is a completely integrated system that relies on high pressure for all braking capability. The accumulator (black metal bulb shaped vessel atop the pump) provides this reserve pressure between cycles of the pump running to build pressure. The pump on it's own cannot maintain the pressure needed to maintain proper brake function. It is used to build pressure within the accumulator which "stores" the pressure charge and will activate the pump again once the pressure drops below a certain threshold (triggered by the pressure sensor switch). The design specs that a full pressure charge on a good accumulator should provide about a dozen normal applications of the brake pedal before the pump needs to run and recharge it again.

Thusly, if the accumulator fails, the system cannot build or maintain the needed operating pressure. The pump will run constantly trying to do so but cannot reach the operating pressure required if the accumulator is bad. If the pressure switch or pump relay fails, the pump will not run and thus the system will not build the required operating pressure even if the accumulator is good.

Simply put, loss of operating pressure equals loss of brakes. When this happens you will get a very hard feeling in the brake pedal such that you can stand on it with two feet and barely move it. At that point you have almost no braking function left. Usually both the red BRAKE and yellow ANTI-LOCK indicators on the cluster are illuminated warning of a failure in these circumstances.

I've experienced this only once in a car I test drove (and declined to purchase based on this issue and several others) and it was a very uncomfortable situation. This was at slow speed in a suburban subdivision (lots of curves and stop signs) and I had to really lay into the pedal to bring the car to a stop.

The single biggest shortcoming of the Teves ABS is the lack of redundancy. If it fails, it is a hard failure that compromises the entire braking system. Most conventional designs will retain some usable braking short of a complete master cylinder/power booster failure, or a complete loss of fluid.

On the other hand, Teves (over)built a good system with greater mean time between failure than most other designs. The longevity and reliability of the Teves setup is a blessing and a curse. The latter because I feel it leads to neglect and lack of maintenance since many uninformed owners consider it out of sight, out of mind. When it does fail, not only is it a bad situation but the system is unusual enough that many mechanics (and most owners) are not familiar with its operation and maintenance. This leads to frustration, especially when the cost of parts is considered.

I am convinced some otherwise decent Reattas have been junked for this very reason. Too many solid, clean cars have been seen in salvage yards with no apparent damage to the body or powertrain. The ABS is a deal breaker if someone considers the cost of major repair or replacement of the Teves components (notably the pump iteself) can be much of the current market value of the car. An informed owner who values the car will not junk it just for this, but a casual owner who bought a Reatta 3rd or 4th hand because it was cheap at the time quite possibly will, not wanting to be bothered with a perceived money pit.

Cost and availability of parts is already an issue, and will only get to be more so in time. I don't worry about it as I know what I have and can do my own repairs. I also specifically chose to collect Reattae, so will not be discouraged by problems that would cause someone only seeking a low-maintenance daily driver (if you want that go buy a new Camry with a full warranty and payments for 6 years) to throw in the towel.

These are the costs and tradeoffs of wanting to preserve an older and slightly unusual vehicle. Most people will not willingly suffer the ongoing inconveniences and foibles of that experince, preferring a car that doesn't require them to be their own expert. That leaves guys like me to do what we do solely out of determination and enjoyment. And so it goes.

KDirk

Thank you for your time and detailed description as to how this system actually works............

The dude abides, don't he.

John F.

I know my comment is unrelated, but am I the only one who is constantly amazed by KDirk's incredible way of explaining things?

Well on Teeves failure you do not lose all braking but it is limited to the front wheels and takes a very firm push (pumping the p-brake helps a little). (You can test by disconnecting the power to the pump, pumping the pedal to remove all residual boost, and then test (preferably on a deserted, level parking lot).

A decade ago there were a few reports of the pedal pushing back and zero brakes which seems to have stemmed from a failure of the main valve. I have not heard of this recently but that is when you pull the gear lever back to low and start pumping the p-brake (and consider going for the big R and planning on a new tranny. Spinning can help here. Just things to consider when the alternative is worse).

Bottom line: never, never, never ignore a red (brake) or yellow (ABS) light. Worst case people have converted to a conventional (Riviera) braking system.

Should mention that all of my cars have ABS and yes ABS can be beaten by an expert if expecting the manoever. There is no warning for Florida ice.

Can somebody point me in the right direction, new member today. I have a 1990 cadillac deville with a leaking abs brake system, seems very expensive to replace and hard to find.

Is it true that i can convert my current system with the Buick Reattas brake system.

Thank

Pretty sure the Cad deVille in 90 used the same Teves as the Reatta. Olds and Pontiac did also.

Thanks Padgett, i think i'm heading in the right direction.

Cal hal

Where is it leaking? If it is a brake line you need to replace/repair it. If it is leaking at the master cylinder it is because you are checking/adding brake fluid wrong.

To check/add you must, with the key off pump the brakes until the pedal gets "hard". Then check the fluid. If it is low on the resivoir sticker you can add. If you add without doing this step you will have too much fluid and it will then force fluid out past the cap. If you have too much siphon the extra fluid out with a "turkey baster" or like item.

What else is going on with your brakes?

Thanks, it's coming out of the master cylinder/ abs unit, seems this car has the big unit with the abs built into it. I took to a mechanic and he said the unit would run$2600, and that's if you can find one. I'm wondering if I can replace with just a master cylinder unit without the abs system. i can't get a solid answer and how to do it. I've been told you can replace with a 1990 buick rivera or Buick Reatta master unit.

I forgot to mention , the pedal went to the floor when I first the car one morning. I had to pump the brake to get the pressure up to get it to stop. That's when i put more fluid in the car, which seems to work fine after I do that.

ABS on that vintage Caddy is not uncommon nor are parts cars for Deville's uncommon. Use you Google and search for parts cars - Craigslist is a good place to start.

Caddy used Teves just like the Reatta through 1990. 1991 models transisitioned to Bosch, as the rest of GM products. ABS was optional on the Deville, usually standard on the uplevel C body (FWD) Fleetwoods and Sixty Specials. Not sure if ABS was standard or optional on the Seville and Eldorado. No idea what the big D bodies used, if ABS was even offered; D body (RWD) from 93-96 used a Bosch ABS setup, standard on all 4 years as I recall.

Anyway, you could find another ABS equipped Deville, FWD Fleetwood or 60 Special from 1990 (lots of these made) to get parts to repair it. Alternatively you could remove the ABS and find a non-ABS 1990 Deville to take the standard system from complete and fit to your car. I do not recommend the late as it is a lot more work, and you lose ABS of course.

I would further advise against taking any non-ABS system from a non-Cadillac (Buick or otherwise) to fix your car as there are probably other differences that may not be readily apparent in the hardware.

Tread carefully here, brakes are one of the things you never want to compromise.

KDirk

Thanks Dave for the brake fluid tip.  I replaced the rear caliber and  added fluid with out the key off pumping.  As a result I was leaking I thought from around the master cylinder.  Did the pumping and it was ready to come out the top when I took the cap off.  remove fluid to the sticker this mornng so I'll watch it for a couple days.  Sounded just like your scenario!