Brake Pedal Feel

[Jim Stoltz]

Last season I replaced both front calipers, rotors, pads and master cylinder. I noticed at that point in time that when the brakes got warm (i.e., lots of use in stop and go traffic or side roads) that I'd develop a loud squeal on the right side. I assumed it was the front but now I'm not so sure. 

But wait, there's more.

This season, first time out to get it inspected (yes, it failed - it's on the to do list) the brake pedal got really stiff and I smelled hot brakes. The smell was coming from the right front, which was smoking when I pulled over. After about 10 minutes it had cooled off and I was on my way. The past couple of trips it has done this, but always cools off either by sitting or driving for a while (like on the highway) without using the brakes.

This past weekend I replaced the right front brake hose, greased up the slides on the caliper and re-packed the wheel bearings. I topped off the fluid and the brakes feel great. No more hot smell from the right side, but still get a stiff pedal when I use the brakes a lot. It always stops - the stiff pedal doesn't affect performance other than making the brakes "touchy" (react too quick). 

What could be causing this stiff-pedal thing? It accompanies brake use so I assume it's something not releasing somewhere but it's not pulling in any direction and it does not seem like the engine is fighting the brakes at all.

[Russell E Johnson]

Do you have a hydraulic powered brake booster?  If so it could possibly be going bad and the accumulator is being discharged by the frequent use in traffic thus resulting in a hard pedal.  I believe, and I may be remembering wrong as it has been 30 years since i worked on one, that the pedal will be hard but the reserve fluid still allows for braking and thus the more sensitive, or touchy, brake sensation.

[Jim Stoltz]

You might be onto something Russ. I do have the hydraulic brake booster. I think the accumulator is replaceable by itself, right? It's that thing that sticks out of the Hydroboost pump?

[Russell E Johnson]

Boy now you are making me stretch, I don't think the accumulator itself is replaceable, or the problem. I think the booster itself is going bad because the accumulator is being depleted the same way as if the engine is not running and you pump the brake pedal.  Wish Jack Wasmuth was in on this, being an ex-mechanic he could explain its operation much better than I can.  I am just a shade tree mechanic and I replaced the entire booster when I had brake problems all those years ago.

[Rich Thomas]

Jim, could it be that there is some air in your system causing a softer pedal then as you pump the brakes or use them in traffic they pump up. I say this because I done a brake job on my car and bleed the brakes. all was fine for a couple hundred miles but the peddle seamed softer than what they had been prior. I was coming home fro a trip and came up on a traffic light and the peddle nearly hit the floor so I double pumped it and got stopped just inches from the car in front of me. A cop saw all this and pulled me over thinking I was tipsy. I know this sounds backwards to your problem but maybe the stiff peddle is normal and the soft is not as it turned out for me. any way just thought I would mention it. If in any doubt at all I suggest you have a pro check them out.

[Jim Stoltz]

Thanks guys. The pedal feels normal but gets stiff after driving. I've assumed it's heat, but it may not be. It's not an un-assisted type feel which would require a lot of pedal effort, the brakes are super touchy when it's doing it.

It does seem much better since I replaced the line and lubed up the caliper.

[Jimco_W001]

Here's one way to check your brakes.Go for a drive and after some stop and go driving use a non contact temp gun on each wheel.If one is hotter than the other wheels than there is your problem.You could even find a bad or under inflated tire using this test.

[Rich Thomas]

Jimco_W001, that's an awesome tip. you can pick up a very accurate temp gun that fits in a shirt pocket from most hobby shops that sell RC cars & trucks. I think the one I have was under $15.00 and runs of a wafer battery. the unit is about the size of a key fob. 

[Jim Stoltz]

I think I have one of those somewhere. It was to monitor the temp in a reptile cage, but if I recall it has a really wide range. Thanks!