1992 Honda Accord LX - Intermittent Brake Hangs and Front-End Shudder

And I'll certainly have the rotors mic'd at the same time. To clarify, the problem never went away with a change of rotors. Rotors were shaved before install, etc., and work done by a shop, not by a shade-tree. I had no more money to pursue the issue then. The problem began to get worse again this summer when the heat set in, particularly these last few weeks since the temps have climbed into the 90s.

I'll be sure to report back ASAP.

Could be simple. Maybe you installed one of the pads incorrectly. Pull the wheels, inspect the calipers, and make sure the brake pad linings are facing the rotor. Or you might have slipped one of the spacers between the pad and the rotor. Or one of the pads might not be seated properly. Check to see that the pads are flat against the rotor.

If everything looks OK, and the rotors are not warped (per the instructions above), pull the pads and inspect them for abnormal wear. Look for pads that are either nasty or showing signs of no use at all--that will tell you something is wrong. Could be you bought el-cheapo pads from WalMart and they are just so badly made in China that they don't fit right. Maybe one has already failed and the lining is chunking.

Finally, you probably have single-piston "floating" calipers. Here, the piston pushes on one set of pads, and the caliper slides back and forth on bushings. If you did not replace the bushings or lubricate them properly, the caliper can hang up, not slide properly, and therefore exerts braking force on only one set of pads. If that happens, the car will not stop properly because you are only using 50% of your brakes.

And change that brake fluid! It doesn't last forever.

Hi Honda Owner,

I have a 94 Honda Accord, and it has a vibration problem on the right front wheel around 60 mph only. It does same after rotating tires.

I am money limited (retired) so I just pump the brake when I am around 60 mph. This may be caused by non-uniform rotor or brake pads surface.

I would be interested to make a fix, but it is not a big concern for me.

DRS

General rule of thumb and a place to start looking...

Vibration around 45 mph---wheel balance.

Vibration around 60 mph---shock absorber/strut.

Hi Accord Owners and Guru's,

Another comment or two:

1. Vibration occurs at same 60 mph range even when NOT BRAKING.

2.Vibration is even MORE SEVER when climbing a hill. (recent problem)

3. Could this be harmonic frequency problem? The drive train seems to have excess mileage on the system.

4. I'm OK at <60 mph, in all situations.

5. This problem has existed for nearly 30,000 miles.

DRS

_____________________________________________________________________

Knowing the problem is 99% of the solution.

Sounds to me like this is not caused by the brakes at all. Braking merely exascerbates the problem, because it puts more stress on the front suspension. Now is the time to look into the halfshafts, wheel bearings, suspension bushings, and other components. Hie thee to a good front end shop for a complete inspection. To do it yourself, put the car on jackstands, crawl under there, and grab and shake everything, looking for something that is loose. Grab the halfshafts, and see if they have slop. Make sure the rubber covers at each end of the halfshaft are not leaking. Put a floorjack under the suspension at each wheel and raise it up and down to see if it moves properly. Grab the tire at the top and bottom and try to move it in and out to see if you have a bad wheel bearing. A good front end shop should do the inspection for free, because they hope to make a fortune on the repairs.

You may be a Slow Old Poop but your writing is concise and accurate.

GA from me!!

Thanks, mate.

Several questions, so bear with me. Your answers can help us go a long way. Are you sure it is the front shaking when your brake? Does your steering wheel jump side to side when braking?

If I am correct, you have 'pressed on rotors'. Meaning that you have to split the hub to take them off and they are mounted by a bearing? If so, did you have your rotors machined on the hubs before installing? That could cause a vibration.

Did the vehicle still shake when the rotors were installed? If so, I would still point to machining the rotors or having hub run-out which requires hub replacement.

If the shaking has gradually accelerated, I would think that your brakes are hanging up. The brakes could hang up due to a few reasons: Brake booster could have an adjustable push rod that come in contact with the master cylinder; if that push rood is adjusted too far, then it could be constantly applying pressure to the brakes. The calipers or slide pins of the calipers could be sticking causing constant drag on the wheels. It is unlikely that the master cylinder is causing the problem, but could go bad as a result of the problem. I would not recommend changing the brake fluid on an old master cylinder as that could cause pressure issues requiring master cyinlder replacement.

Any information will help.

Sometimes when replacing pads, if the caliper piston isn't removed and a hone used to resurface the caliper bore, when the caliper piston is pushed back into the caliper bore, the piston seal doesn't shear off the crud build-up on the caliper bore wall, causing the piston to hang up and not fully release the rotor (as well as possibly ruining the seal). This causes heat build-up and warpage in addition the increased pad wear on that corner. Check that pad wear is relatively even side to side.

Driving style can also contribute to warpage. You are decending a long hill. Do you apply the brakes and hold them there to maintain speed or do you periodically apply them relativley hard for a short peroid to reduce speed then release to allow them to cool? When you come to a stop after a downhill or stop in traffic light traffic, do you release the brake to allow the rotor to turn slightly and move the hot spot under the pad to get cooling air? Over time, this can cause warpage.

Well put.

This one of the reasons why I used to keep a tin of "used" brake fluid, to wash off and soften any dirt that might be stuck on the pistons, before pushing them back.

I have noticed though that most cars that I have had over the last 20 years or so have a rubber bellows (for want of a better word) that stops the piston getting dirty as it extends out.....but I guess not all cars are so equipped even today.....

Whats the general take on cars say since 2000 on this particular point?

I don't have enough background to be knowledgeable about the vast numbers of vehicles out there but I am of the opinion that at least a majority of manufactures consult/contract with major brake system manufacturers when designing vehicles. Bendix and such. I personally have not owned a vehicle that didn't have a "dust shield. What I was referring to, though, was the square cross sectioned "O-ring" that fits into a groove around the piston, that seals the fluid chamber. As the pads wear and the piston progressively repositions itself outward in the bore, various sorts of dirt and scale build-up behind the seal. Being subjected to multiple heat cycles, this build-up becomes quite solid and requires a little more than "boy, I hope it cleans up when I push the piston in". Doing this can tear out little chunks of the rubber piston seal and cause seepage and, rarely, caliper failure. Additionally, corrosive (oxygen) elements in that scale can pit the walls of the bore, providing an abrasive surface to wear away the rubber seal and an additional path for seepage. With all this seepage, if a vehicle isn't periodically inspected and maintained, the brake fluid level in the master cylinder can decrease to the point where bubbles of air are introduced into the brake hydraulic system creating a marked reduction of braking efficiency, first a spongy brake pedal progressing to the inevitable OMG!!! reaction.

Any time there is access to the caliper or any brake slave cylinder, observe if there is any evidence of fluid leakage. If possible, carefully pull back the dust shield and look for any dampness.

Keeping the master cylinder topped up is a two edged sword. When all brake pads and/or shoes are new, the master cylinder should be full. As the brakes wear, fluid is drawn into the system as the pistons relocate to take up the thickness loss of the friction material and the fluid level in the reservoir decreases. Baring any fluid loss through leakage, systems are designed to hold enough fluid so as to not decrease below a safe level. I'm not saying that topping up the reservoir is a bad thing but when it comes time to install new brakes again, be aware that when pushing the pistons back into the bore, it is possible to cause the reservoir to overflow. Messy, but one of those "I'd rather error on the safe side" things.

I am very critical of your non replacement of the fluid, this can be tantermount to suicide......but its not the problem you have....yet!!

The problem is probably that you neglected to clean under where the disks go after removing the old ones.

I use a wire brush in a drill (and leather gloves and eye protection) to clean intimately this area.....

This dirt is causing the disks to not sit flat and now they have a "wobble!".

Clean the new disks in that area as well now as they are dirty....even a single grain of sand can cause problems....

Note: new rotors were professionally installed.

Looking for information elsewhere, I think I found the answer. First, an update.

I left for a short trip north on Saturday and found the vibration too much to abide once more. While still on the hi-way, I began to brake as I took the off-ramp and I could feel a hard pull to the right as though the right front caliper were engaged first--very bad shudder when doing so. I managed to slow coming off the ramp, found a safe spot on the shoulder and pumped the pedal several times. Back on the hi-way, same issue, pulled off again, found an empty lot, let the car idle for a bit. Once again, I got back on the hi-way, and once again the vibration began. For some reason my mind said attempt to slow with the emergency brake to get me down to a slower speed before applying the brakes via the pedal.

Here's where it got interesting:

At a speed of 70MPH with bad shudder, no brake applied, I pulled the e-brake a click and immediately the vibration lessened. My speed did not slow enough (below 60) to have caused the cessation as if it were only a wheel-balance issue. I even accelerated with the e-brake set ever slightly and the shudder remained less than without the e-brake engaged. I got off at the next exit, maintained city limit of 40MPH which was still fast enough for there to be shudder in the front-right and several times I re-engaged the e-brake slightly to see what would happen. Each time, the shudder lessened, though it did not disappear entirely.

Today, on another forum, I found somebody asking about a similar issue and the thread discussion turned to the master cylinder and an explanation of how fluid is routed, with the suggestion that the MC was the culprit.

From what I gather, there are two valves in the MC. Logic would suggest that each valve controls a pair of brakes, but rather than FF and RR, one valve seems to control LF/LR and the other RF/RR with the latter being the first to charge?

Thread starter on the other forum took the advice of swapping the MC and reported the issue resolved. As his problem was also shaking in the RF, I'll go with the same suggestion and have the MC replaced and the fluid flushed/replaced.

Keeping fingers crossed that this will take care of it. I don't think the calipers are shot at this time as when the brakes are working correctly, braking is smooth.

Thanks!

Only some cars cross the brakes LF RR and RF LR, and those are usually late model cars with 4 channel ABS systems! Partially setting the parking brake only causes drag and then only on the rear wheels. It can reduce wobble or shutter, but that only happens when the rear brakes are drum type and not disk brakes! I would still be interested in checking the run-out with a dial indicator at each wheel!