michaelost

Hello, the new brake booster arrived today and I installed it this afternoon: Everything is ok again, car brakes fine, pedal comes up!

Hi everybody, maybe I trapped the sticking brake pedal problem! This is what I did today: 1. I narrowed the rubber hose between the brake booster valve and the filter with pliers, so that less vacuum was provided: At idle (700 rpm) the brake pedal didn't stick, but the booster worked. I tried this several times pushing the pedal very hard, it always came back. 2. I reved the engine at higher rpm (about 2000), the pedal stuck once and a time. 3. I fixed a 6 mm (outer diameter) copper hose like used for brake lines between booster valve and filter (see pic) and test drove several miles, used the brake until the wheels blocked, braked very hard several times, also in gear L2 and L2 (for higher revs), THE PEDAL ALWAYS CAME BACK!! So my conclusion is: Your first guesses were right, it's the (new) brake booster which somehow doesn`t get along with the vacuum provided by the engine. Am I right? Nevertheless I ordered a new brake booster which will arrive next weekend. Cheers Michael

Correction: 7/16" is wrong, so would this one be the right one? https://www.amazon.com/Williams-35212-2-Inch-Socket-8-Inch/dp/B007YR9UXK/ref=sr_1_11?s=hi&ie=UTF8&qid=1536749186&sr=1-11&keywords=3%2F8+hex+bit+1%2F2+drive Very difficult to get here in Germany

But I measured 11.1 mm which should be a 7/16'' head...

Hi, I have another question: which tool do I need to loosen/tighten this brake caliper bolt? In all my tool boxes (with German measures) there is nothing that fits ! Thanks for your help Michael

Hi, unfortunately I dumped the original part, stupid :(!

Thank you very much for your advice! So I think I'll have to order another brake booster. Any idea which one would be the best: https://www.rockauto.com/de/catalog/buick,1980,riviera,5.7l+350cid+v8,1021644,brake+&+wheel+hub,power+brake+booster,1884 The last one I had was the A-1 Cardone.

I did this test and it was ok...

Oh my dear! I bought mine a couple of months ago at rockauto and it was a great mess to change it lying under the dashboard !

Brake Problem 79 Riviera 4 wheel disc brakes Hi from Germany! My Riviera has this problem: Sometimes (engine on) the brake pedal sticks after hard braking and comes loose again after a few meters of driving. Brake booster and master brake cylinder are new. I did the brake booster test (engine off, some steps on pedal until hard, engine on, pedal goes down a few inches) and this was ok. When the pedal is stuck (at idle) and when I remove the valve from the brake booster the pedal comes up! There is a lot of vacuum on the hose and the valve is ok. I exclude problems with calipers, brake hoses, because when I use the brake with the brake booster valve disengaged everything is ok (with the exception of course that I need much force to brake). I would very much appreciate every hint what I can do next and how to solve the problem. Cheers Michael