Hey Fellows
I am at my wits end. Every time I slowly stop I hear a loud clunk and my break pedal goes down almost to the floor. I have taken this little fellow to three diffenent shops and all three have given me a differant answer as to what the problem is. I don't think any of them have a clue and mostly just want to replace every thing that has to with breaks.
Oh, its a 2002 mazda 4.0 with 55,000 miles. If anyone has had this problem could you please clue me in? Hell-I'm not made of money.
Thanks muchly in advance

 

Well seeing as how brake fluid doesn't compress much, it sounds like you have excessive mechanical travel in the shoes or pads at the wheels, or you have air in the lines.

SO, is the pedal soft or spongy, or firm, when this happens?????

If it's soft, you likey have air in the system, so have you checked your brake master cylinder fill level lately????

If it's firm, then it's likely excessive travel in a wheel cylinder. Seeing as how the rear shoes are mechanically self adjusting & that system often has problems, I'd put it high on my check list.

Does the "clunk" sound seem to come more from the rear wheels, front wheels, or drivers side firewall area???

Do you have a trouble light lit????

Did this condition come about slowly over time, or suddenly, after some event????

DON'T put off getting this resolved, as it's a big safety item & those brakes are crying out for attention!!!!

 

Thanks for your input Paw Paw. Yes, I have a firm peddle and its seems the "clunk" is comming from the front wheels. There are no lights on the dash or codes displayed. That's why each mechanic I take it to suggest changing out something differant in the system. No one down here seems to have seen this problem before. Man,I have all the luck.
Thanks again
Cracker500

 

OK, well firm pedal suggests there isn't air in the system.

So it would suggest to me, that you have excessive travel in one or more of the wheel cylinders.

You didn't say if this happened suddenly, after some event, or slowly over time.

So did this happen suddenly or maybe after a repair or service????

Have you had the rear brake shoes inspected & or adjusted?????

How about the front calipers & pads???

If the rear self adjusters aren't working properly, the shoes can be too far away from the drums & will require more pedal movement to have them make contact & that can cause a low but firm pedal.

You could try backing up & stomping the brake pedal hard, to slow some, then repeat that several more times & see if the rear shoe self adjusters, will take up enough slack, to bring back normal pedal height. Or check/do the adjustment yourself.

I suppose you could also have a sticking front caliper, with worn pads & that could cause a thunk, when the sticking caliper breaks loose & the worn pads would allow more travel before contacting the rotor & that would cause the pedal to drop, but still be firm.

What year, model, vehicle & mileage on the brakes????

Just some more questions & brainstorming thoughts to ponder!!!!

 

I think Paw Paw is right. One of your callipers is suddenly moving way too far. Mabey a front pad is really loose and is rotating forward causing a clunk. Mabey your whole caliper is loose. I think a bad front wheel bearing could cause the rotor to wiggle and compress a front caliper and the clunk on brake engagment too.

Just jack up your truck on 4 jack stands and take off the wheels. You will probably find something that has been clunking around and looks beat up or some part will be way looser than the same part on the other side. Firmly grasp and wiggle pads, Shoes , wheel cylinders, back plates, calipers rotors and anything else you see and you will probably find the culprit. Then if you don't want to fix take it to a shop and pay for only what you actually need not the full lube job.
Nick

 

I recently took off my drums in the rear and found that on the driver's side, the adjuster cable had snapped. I was about to do the brakes anyway as I had noticed a soft pedal feel. The pedal feels much better after I rebuilt the rear brakes with new hardware. I imagine that as paw paw said, there was a lot of room for the shoes on that side to move before they met the drum since they weren't adjusting.

-Jim