Not sure if i should be scared or What? I hadn't driven the car in about a week due to crummy weather, started the car and the brake pedal felt really hard to push on. Carefully and slowly pulled back into garage and took my faithful Ford out. A few hours later, came back and tried again and pumped the brakes about ten times and got the normal pedal feel back and now everything seems fine. Took her for a long drive and np. 1985 Mondial 308 QV... My question is...should I be worried that this happens while I am driving it? Anyone have this happen to them? Since its working fine now, how would you trouble shoot something like this? All I can tell you is the brake fluid is ok. Thanks for any advice.
If nothing else, I would change the brake fluid. Examine the old fluid for water, rust, other contaminates. Proceed accordingly.
It sounds like a classic case of a sticking "check" valve in the vacuum hose to the power brake servo. If the valve sticks "closed" there will be no power boost for the brakes. You will have a high, hard pedal and very weak brakes. Once it "un-sticks" the brakes will return to normal. Try a search for "check valve" or "power brakes" etc., it's a fairly common problem and has been discussed several times before. Easily fixed, just remove the valve and clean it out with some carb cleaner.
Mike is right. My 328 did the same thing when cold...first stop in the morning, out of the driveway...then worked fine the rest of the day. New check valve...and all was well.
I recently had a very similar experience ith an '85 308 myself. It was due to "Big Cam Itis". That being the consistantly low manifold vacuum that is part of longer durations effect on low RPM running. Ya gotta live with it. Or maybe not. I started to back out of the lift bay, fresh motor bubbling away,and got a pedal much like you are describing. Whoa! No way was I going out on the road with brakes that felt like that. I'm fun lovin', but not into suicide! I got into the system and checked the one way valve. I tested it, and it took an average of 5" of vacuum to open it. Heck, all I had at an idle was 10". This meant only 5" was actually getting foreward to do the work. So fresh fluid flushing, new SSlines et al was not doing squat. Check out this URL: http://www.durable1.com/brake.htm Stewart Chung was kind enough to loan me his 308 so I could get the dyno #'s for a new product,and I put one on his, even though they are marketed for "Track". Delightfull! As I automatically double clutch down shifting before corners as a force of habit,( I'm not alone there am I?) I noted it had even more vacuum due to the engine braking,I qiuckly noticed that the pedal was more solid feeling,and the car felt like it just had new brakes on it. It took perhaps 2 seconds to figure out I could drive deeper into corners than I had before, as the brakes worked better. Been having a blast since! Enjoying the drive! Kermit
Kermit, Excellent! As soon as things warm up a bit here you KNOW i will be installing it Keep up the GREAT work!
I searched and couldn't find any thread on cleaning the check valve. By the way the old ferrari chat search doesn't work anymore. Can anyone give me a clue as where to find the valve and how easy it is to clean the check valve on the braking system. 1985 Mondial QV.
