I have recently replaced my rotors, pads, Master Cylinder, bled the brakes.
When I was driving home from work today, it started making a thumping noise when I initially press the pedal. It sounds like a loud thump coming from the firewall. I stopped at a mechanic on the way home and they couldn’t figure it out either. They thought it might be the booster but the booster seems fine other than the noise. It is intermittent too. It doesn’t do it every time I press the pedal. The mechanic said it could be the pedal itself but it looks ok.
Has anyone ever experienced this one too? Could there be a crack on the booster causing a noise when activated?
Any help would be great since I do not want to have to replace the booster unless I absolutely have to…we all know what a pain that can be.
You get this only intermittently, and only when you initially put your foot into the brakes?
You replaced the rotors, pads etc.
Is the thumping rhythmic? Does the thumping slow down as the car slows down? (I know you said it goes away during braking, but you should be able to tell if the rhythm slows down a bit.)
EX: ddddd.d.d…d…d…d…d…d…d…d…d…d…d…d
My guess:
Brake pad material is sticking to the rotors in one spot. Your wearing it off as you slow down, but its continually happening as you drive the car.
Did you break the brake pads in? Did you do the, “Come to almost a complete stop 10 times in a straight line quickly?” kind of break in? Accelerate, get going pretty fast, brake hard, but do not actually stop, get to ~5 - 10mph then get up to speed again. Rinse and repeat ~10 times as quickly as you can. Some people have different ways of breaking the pads in, this is how I was taught.
Or just throw them on the car, bleed the breaks, and go about driving your car?
Rotors and pads were changed a month or so before the master cylinder was replaced. Brakes were bled after the pads and rotors were changed. Bled again after master cylinder was changed.
The noise does not continue while the pedal is depressed. It only makes a thumping noise when I initially depress the pedal. It does not happen everytime I push the pedal either. It hasn’t made the noise in about 48 hours. I stopped by a Honda shop that does performance stuff and they couldn’t quite figure it out either. They thought maybe it was the pedal assembly hanging up and making a noise? We sprayed the springs with Silicon spray and it still made the noise. Everyone seems to think it has something to do with the booster but nobody is for sure? I was just wondering if anybody on G2ic had this same problem?
I guess I am going to have to get up under the dash and remove that stinking booster and check it out! Oh well, wish me luck!
Ok, so you get 1 thump when you push the pedal. But it does not happen all the time.
The booster isn’t under the dash. Its under the hood. Its what the MC attaches to.
One thing that might cause a “thump” or “click” is the adjustment rod in the booster, or the joint pin (which the helms says should be lubed). Though I could see more of a click or a catch and slip type feel than a thump.
But both of those would give you a funny feeling pedal I would think.
Yes, it is more of a thump type loud click and it only happens one time. The Honda shop mentioned the adjustment rod in the booster, or the joint pin but did not say h ow to lube it. My understanding is it is difficult to access the booster since it is right behind the master cylinder and you have to remove a lot of stuff to access the booster. Is the adjustment rod near ther engine side or firewall side of the booster? The took off the master cyclinder and did not see any problems with the booster.
The booster is the round canister the Mc bolts to. It also has an arm that goes through the firewall, and ends up connecting to your brake pedal.
I have never taken the one off my teg, but I have replaced them on GMC full size trucks and full sized cars in the past.
The helms says to just oil the pin, and to measure from the baseplate of the booster to the end of the push pin should be 4.6in ± 0.02in.
There is a gauge you can get from Acura (pt#07JAG-SD40100) to measure that length, and there should be 0.008in of play between the push pin and the booster.
Unless the bushing for the brake pedal is worn out completely, and binding/catching/popping, the above is the only other thing I can think of that would give you what your seeing/hearing/feeling.
BTW, if it is the bushing for the brake petal that is worn out, I do not see any replacement for that bushing in the helms manual. It appears to be one assembly. Maybe try shooting some oil on it?
(Do not WD-40, its not a lube, its “Water Dispersal version 40” It has lube properties, but its main intent is to get rid of water, not lubricate)
I recently replaced my Master Cylinder and have this same exact problem. I didn’t oil the pin when replacing, would that be the reason this is happening? P
The problem is the same as the first posting: intermittent thumping sound when applying the brakes (it sounds like it is coming from the brake booster). I want to make sure this isn’t a safety issue. I did not lube the brake booster pin. This happen almost immediately after I installed the master cylinder, so it has to be related.
Did you make sure you have the correct distance? It is more likely that you have slack in it causing the noise, than no oil causing the noise. I personally would pop it back open, oil it, and make sure you have the correct gap in there. Sounds like you have too much gap.
I ended up having to change my booster out. I also had this popping noise, though it was way after I posted her initially and had forgotten about this post. after replacing the booster, and adjusting the gap, all is good. Though my reason for replacing the booster had nothing to do with a noise, it had everything to do with no brakes!
Remember, if you have that rod too long, it will constantly apply pressure to the brakes, it will cause you to “ride the brakes” all the time.
Sent to me by someone via email:
> ok,
>
> I took it into my mechanic and he said he has never adjusted the gap on these and is insisting that the problem is the MC is from Pep Boys. What do you think about that?
>
I am guessing this is “fragment”, though other than the paragraph about this being confidential email, from a work address (did not copy that here), I have no clue who this person is.
I am sure he will say many things, and we can only hope he is telling the truth, I hope he is, and not dicking you over.
Almost never? Ya, just because one car or other cars do not have this problem, does not mean you do not. Mine did. Glad I didn’t use your “mexhanic”, I might still be paying him money to find the noise.
I would also like to know how a MC could make this noise.
My squeaking in my front suspension was my lower ball joint, everyone said it was the ES bushing, or my coilovers, and had never heard of a BJ swquaking. I took a chance, and replaced a BJ that did not even feel bad, it was my problem. It had no grease in it.
If this mexhanic has never steered you wrong, then trust him I guess. I do not know you or your car from a hill of beans, if he does, he might be the better choice.
I’m having a simillar problem with my 92 teg when i press the brake pedal under heavy straight braking i get a thump right under the floor board under my pedal and foot and when i start going again it thumps back and goes away just like that i also have a full swing of new brake parts OS Powerslot rotors front and rear EBC Green Stuff pads all the way around New MS New lines hard and soft and Delete PS any ideas? i’ve had it on a lift and i cant find anything i thought maby the previous owner might have lost a tool in the frame rails and when i hit the brake it slides up to a stop then slides back but i dunno, it does not affect the brakes in any way tho no loss in performance or driveability
yes sorry, i should have clarified (that was me and thanks for not posting my email). Just getting frustrated, not sure what to do at this point. Do I need to purchase a special tool to adjust the GAP?
I too had a sound more like a ‘clunk’ when i initially step on the brake…but i fixed it. you know what it was…it was the small screws on the hub, it was halfway out, broked 3 axles before i figured that one out. i tightened it down…and now it runs good again no noises. hope this helps. if you find out what your problem was, please share.
(quote) shifterkart1 I too had a sound more like a ‘clunk’ when i initially step on the brake…but i fixed it. you know what it was…it was the small screws on the hub, it was halfway out, broked 3 axles before i figured that one out. i tightened it down…and now it runs good again no noises. hope this helps. if you find out what your problem was, please share.
Thats not it thanks for the advise tho worth getting checked out i think theres a ratchet in the frame haha and ill just be cursed with it
ok, so I really disliked having to bleed the system and dealing with the thumping sound. I wasn’t about to do that all again and then want push my car off a cliff after doing the same thing. I let my mechanic install the part from his source, and no more thumping. He determined it was a defective MC.
I like working on my car, but not when dealing with this crap. If I could do it all over again I would have bought the OEM Nissin replacement MC from Ebay for $100 that someone linked.
