Brake Flush Question

[Guest imported_JohnW]

I've talked to 3-4 brake shops and 3 Buick dealers about flushing my brakes. The responses range from "GM does not recommend it" to "No Problem - we can flush all brakes.

My questions are...

1. Is the procedure for flushing the Reatta's brakes the same as other ABS systems? I offered the shops the flushing instructions from the web sight but they say they know what they're doing. I'm no brake expert so I need to put my faith in someone.

2. Since I have no idea when or if the flushing was performed prior to me owning the car, should I start putting some penetrating oil on the bleeders? If the bleeders are frozen and can't be removed, are rebuilt calipers the only answer? I don't know if any of the shops I talked to will attempt to drill them out if they are unable to remove them.

Thanks for the advice in advance

John

[Guest Greg Ross]

Generally Dealers and "Franchise" Shops know it all-not!

If they arn't willing to accept guideance from you in the form of Flushing Instructions specific to this type system, walk away (or as EBSO says "RUN"). You want to find a "NoName Shop" gernerally privately owned and the Owner works on the shop floor or directly supervises it. This type business is usually willing to try and develop reletionships with returning customers.

I travel a great deal and when I land in a new locale the first order of business is to find a shop I'm comfortable with. Tell them up front the car is a Keeper, treat you fairly and you'll be back for all your maintanance. Best guy I ever had specialized in Imports-Bimmeres etc. but he was GM Tech Trained originally while he worked for a GM Shop. Ask around for referrals, be patient and you should find the right shop.

[Guest wally888]

My only experience with flushing is the Manual procedure outlined in the FSM. A better explanation is at reatta.net

Hope someone will explain the difference in using a Pressure Bleeder and a Vacum Bleeder? As I remember, no longer have FSM (have 91) the FSM recommends a Vacum Bleeder?

Having used the manual procedure twice (use system pressure for rears, manual pump pedal for fronts) and having opened all bleeders on 4 cars (16), I had no frozen bleeders! Think the wrench size is 8mm.

If you have a willing helper suggest you read instructions at reatta.net and do yourself if shops keep up the B.S.

[Barney Eaton]

The unique thing about the Teves hydraylic system is the pump side must be flushed/purged before the rest of the system. If the shop does not do this all that brake fluid in the accumulator will contaminate the new fluid put in the resevoir.

I recommend talking to a VW or SAAB shop .... these cars used the same system at the same time as the Reatta and they are more likely to understand the requirements of this system.

[2seater]

There is essentially no difference between pressure bleeding and vacuum, they are both using positive pressure at the master cylinder to push fluid through the system. The pressure bleeder is easy to understand since you are adding to the existing atmospheric pressure to push the fluid through. Applying vacuum to the other end of the system, at the bleeder, allows atmospheric pressure to push the fluid through in the exact same manner. An approximation of the pressure generated at the master cylinder is one half of the amount of vacuum created at the bleeder. In other words, if you can pull about 29+ inches of vacuum at the bleeder, you will have approx. one atmosphere of pressure,(about 14.5 psi at sea level), differential acting on the master cylinder. I have used both with equal success, however the automatic refilling of the master cylinder with the pressure bleeder makes life a lot easier. I made my own pressure bleeder for not much money, with a two quart capacity. I hang the pressure bleeder higher than the master cylinder, and use the first quart without any pressure in the bleeder. I let the rear brakes bleed themselves using the onboard pump, and use about 1/2 of the fluid in the bleeder. I then pressurize the bleeder to 12-15psi and push the rest of the fluid out through the front brakes.

[Guest EDBS0]

The preferred method of flushing (not bleeding) from a shop that I frequent, is to let gravity do the work.

Top up the reservoir and open the bleeder and let it drip out until fresh and clean fluid flows. This way you will not mess up any internal valving etc.

Pressure and vacuum bleeders are <span style="font-style: italic">"toys for boys".</span> they make the job fun but are not necessary.

Penetrating oil on the bleeders won't hurt. My 89 from Texas was/is almost completely rust free and opened freely.

If you have a couple of hours this is a DIY with little to mess up.

[2seater]

It would seem to me that the flow rate to flush the system would be too low if just left to dribble past the valves and small ports in the system. If the system is pretty clean to start with, it would probably work fine to change the fluid. Toy, no; tool, yes