michaelost Posted September 6, 2018 Share Posted September 6, 2018 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 Link to comment Share on other sites More sharing options...
Seafoam65 Posted September 6, 2018 Share Posted September 6, 2018 You have a defective brake booster. Link to comment Share on other sites More sharing options...
michaelost Posted September 6, 2018 Author Share Posted September 6, 2018 6 minutes ago, Seafoam65 said: You have a defective brake booster. 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 ! Link to comment Share on other sites More sharing options...
michaelost Posted September 6, 2018 Author Share Posted September 6, 2018 I did this test and it was ok... Link to comment Share on other sites More sharing options...
Seafoam65 Posted September 6, 2018 Share Posted September 6, 2018 If the brake pops up when you remove the check valve, the booster is the cause of your problem. In my shop we get bad brake boosters all the time and have to do the job twice, no surprise that you got a bad one. Link to comment Share on other sites More sharing options...
michaelost Posted September 6, 2018 Author Share Posted September 6, 2018 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. Link to comment Share on other sites More sharing options...
Seafoam65 Posted September 6, 2018 Share Posted September 6, 2018 Any brand is a crapshoot........the Cardone is defective about half the time in my experience, might as well try the Rock Auto brand. Link to comment Share on other sites More sharing options...
telriv Posted September 6, 2018 Share Posted September 6, 2018 MANY of the re-builds are actually from A-1 Cardone. So no matter where you get one they will ore than likely be the same. Best off sending it too Booster Dewey. Then you KNOW it will be correct. I know it's a hassle being in Germany but there really is no choice. Do you still have your original??? Hopefully you didn't turn it in for the core value. If so send the original one. 2 Link to comment Share on other sites More sharing options...
michaelost Posted September 7, 2018 Author Share Posted September 7, 2018 Hi, unfortunately I dumped the original part, stupid :(! Link to comment Share on other sites More sharing options...
michaelost Posted September 7, 2018 Author Share Posted September 7, 2018 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 Link to comment Share on other sites More sharing options...
Seafoam65 Posted September 7, 2018 Share Posted September 7, 2018 You need to purchase a full set of non metric American sized Allen head sockets and of course a full set of American sized non metric end wrenches if you don't have them for working on your car. Also a clutch head screwdriver set. Link to comment Share on other sites More sharing options...
telriv Posted September 7, 2018 Share Posted September 7, 2018 That bolt is "Normally" a 3/8ths. Allen head. Link to comment Share on other sites More sharing options...
60FlatTop Posted September 7, 2018 Share Posted September 7, 2018 I use a 3/8" Allen head 1/2" drive socket for that bolt. You can grunt pretty good on those. Bernie Link to comment Share on other sites More sharing options...
Paul K. Posted September 8, 2018 Share Posted September 8, 2018 On 9/7/2018 at 2:10 AM, michaelost said: Hi, unfortunately I dumped the original part, stupid :(! Lesson learned. You live in another country. Don’t throw anything away. ? Link to comment Share on other sites More sharing options...
michaelost Posted September 11, 2018 Author Share Posted September 11, 2018 On 9/7/2018 at 11:41 PM, 60FlatTop said: I use a 3/8" Allen head 1/2" drive socket for that bolt. You can grunt pretty good on those. Bernie But I measured 11.1 mm which should be a 7/16'' head... Link to comment Share on other sites More sharing options...
michaelost Posted September 12, 2018 Author Share Posted September 12, 2018 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 Link to comment Share on other sites More sharing options...
michaelost Posted September 12, 2018 Author Share Posted September 12, 2018 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 1 Link to comment Share on other sites More sharing options...
SwedeDownUnderR63 Posted September 12, 2018 Share Posted September 12, 2018 6 hours ago, michaelost said: 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 I don’t know if that is the correct one. Just letting you know I have found Eastwood.com a good place to get special tools from for an acceptable price (although I can order almost any kind of tool at shops in Australia but often for a higher price than in the USA). 1 Link to comment Share on other sites More sharing options...
telriv Posted September 13, 2018 Share Posted September 13, 2018 Get a 3/8ths Allen wrench. Cut it to the proper length, about 1 1/4", & use a 6 point 3/8ths. deep socket on your ratchet. Allen wrenches are relatively in-expensive & you may have the 3/8ths. socket in your tool box. Tom T. Link to comment Share on other sites More sharing options...
michaelost Posted September 13, 2018 Author Share Posted September 13, 2018 Hello, the new brake booster arrived today and I installed it this afternoon: Everything is ok again, car brakes fine, pedal comes up! 2 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now