Need help diagnosing potential brake problem

[youdontwannaknow]

This is for the accord in the sig.
Pads are oem and almost new(80-90% left), brake fluid replaced (vacuum method) but brakes feel soft, braking power is lacking. Requires quite a bit of foot pressure to really get responsive braking at highway speeds.
Another thing is that there is a fair amount of pedal travel before I can feel brakes really even engaging. I'd say a good 50% before you can feel any braking effect.

What could be going on ? What can I check and do to restore braking capacity ?

 

[Johnny248]

Brake booster?

 

[sunfire]

What about your rear brakes? Have they ever been replaced?

 

[CBR.worm]

Is it worse since replacing the brake fluid? You could have sucked in some air in which case bleeding it (again) might help.

Some cars with ABS have a specific procedure to follow to bleed properly.

 

[spasm3]

A couple of things here. First rebleed them starting at the wheel farthest away, never let the brake pedal go all the way down to the floor. I would bleed them with a friend and for get the vacuum since you are having trouble. Second after bleeding it pedal travel seems excessive you may need a master cylinder. Do check the brake lines first, as they are 11 years old.

 

[KrisZ]

Originally Posted By: sunfire
What about your rear brakes? Have they ever been replaced?


+1

Check if they are worn out, if not they are probably out of adjustment, this is all assuming you have rear drums.

Sometimes drums fail to automatically adjust and it has to be done manually.

 

[youdontwannaknow]

No ABS. Rears are drums but were checked as part of "brake inspection" when I took it in for front brake job. I dont believe any adjustments were made though.

So bleeding them at the lines instead of vaccum method would be more effective ? When I said it needs more foot pressure it feels sort of spongy. My first thought in all this was that there is air in the lines but I ruled that out since the fluid was just replaced.

 

[oilboy123]

Bleeding with vacuum is fine, but I would do the last part of the bleed using a foot on the brake pedal. This will make sure you don't pull any air into the system.

I concur on the rear adjustment. How does the pedal feel with the boost vacuum all used up?

 

[spasm3]

Originally Posted By: youdontwannaknow
No ABS. Rears are drums but were checked as part of "brake inspection" when I took it in for front brake job. I dont believe any adjustments were made though.

So bleeding them at the lines instead of vaccum method would be more effective ? When I said it needs more foot pressure it feels sort of spongy. My first thought in all this was that there is air in the lines but I ruled that out since the fluid was just replaced.

If they feel spongy there may be air in there. Manual bleeding them may be more fool proof. Have a friend press the brake pedal down, open bleeder, close bleeder before you have your friend release the pedal. repeat multible times at each wheel, starting at the farthest away then the closest. lr rr rf lr. My wife is very familiar with the instructions "press, hold... release" !!! she hates helping me bleed the brakes.

 

[Quest]

check brake booster.
check brake system for air bubbles in hydraulic systems (purge them when necessary)
check all brake hoses esp. rubber hoses for signs of swollen/soft rubber. replace them when necessary
check brake pads for glazing. Bed them by roughening (deglaze) the rotor and wash down the friction surface of rotors with brake cleaner.

If at the end of all this still no improvements, your master cylinder is shot (leaking fluid pass the cup) and is in need for a full replacement.

Q.

 

[Scott_Tucker]

To check if the rear drum brakes are out of adjustment, apply the hand brake while driving and see if the pedal feels firmer. If it does, your rear brakes are out of adjustment.

 

[Vikas]

Here is something that you can try on your Honda. Get it someplace safe and open like a deserted parking lot. Put it in the reverse and get it up to some speed (say 10mph) and *slam* on the brakes. Do this repeated times. If your rears are working a little bit, this will "auto-adjust" them. This only works on the Honda like systems where they have this mechanism and only if they are not completely out of adjustment and the mechanism itself is not frozen.

But it is worth a try before you take it to a shop.

Here are few things you could answer:
- If you pump the brake pedal, does it brake better?
- How many clicks on the parking brake before it locks up
- When the parking brake is locked, can you stall the engine i.e. is the parking brake working as it should be?
- Do the brakes behave differently when they are cold vs warm?

- Vikas

 

[mechtech2]

Those rear drums are my first guess.
All sorts of parts need to be lubed, and there is an internal adjuster, as well as the parking brake setting.
A long but otherwise good pedal would point to them.
But, you probably have multiple issues, small and large.
Bleeding can be a problem.

One quick test is to step on the brakes a number of times with the car off. The pedal should get hard and rise up.
If it is low and hard, try using the parking brake, then step on the pedal. That should raise it up. If it does, that is further evidence of rear brake drum faults/adjustments.

 

[eljefino]

You could also have a siezed pin in a caliper. This would lead to the bad braking and because the pad is way too far back and getting cocked sideways, the mushy pedal. If this were going on it might also pull.

 

[youdontwannaknow]

I am leaning towards a rear brake adjustment now as well. Now that I think about it, I dont think thats been done in a while.

I did the brake booster test(pedal rise and harden up with engine off) as provided in the serv manual and everything checks out fine.

Parking brake takes a good 6-7 clicks to hold car on a slight incline (like a driveway).

Pulling the hand brake and then applying brakes does make it a little more responsive and there seems to be an improvement in the pedal as well as brake response.

As for cold v/s warm braking resonse - yeah I think cold braking is a little mushy then warm.

 

[mechtech2]

Like eljefino said, the front calipers can of course be sticky.
Be aware that you may have multiple problems that compound each other. Brake systems are like this.

 

[youdontwannaknow]

ok, adjusted the rear brakes. they were off some and while there is an improvement, it isn't a whole lot. I'd say full pressure stopping is better now but low/mid pressure and pedal travel is not much better.

I am hoping that when they(dealer) replaced the front pads and resurfaced the rotors they took care to lube the whole caliper pin and all. And the car doesn't pull while braking.

Now the pads are oem, but the rotor is aftermarket. I dont know what it is though. Could there be a rotor-pad mismatch ?

 

[Scott_Tucker]

A stuck caliper pin won't cause a low pedal. You likely have air in the system. Try bleeding next.