Brake Pedal Issues - Toyota Nation Forum : Toyota Car and Truck Forums

zppeacock · 01-02-2011, 12:34 AM

I got some issues with the height of my brake pedal. Previously the car was sitting for about 5 years getting moved once or twice a year. Before the car was parked it had good working brakes.

I have a extremely low pedal. System has no leaks, rear wheel cylinders have no leaks, drums are rusty, adjusted rear shoes back into adjustment, new pads and rotors front, 1 new caliper passenger side.

Bled the brakes in the proper order didnt get much air out of them expect the one with the new caliper, pedal gets better until the car is moved then drops back down to where it was before.

Pedal isn't mushy its just about 1/4 inch from the floor. I'm thinking its the master cylinder but any opinions would be great.

ganda1f · 01-02-2011, 05:59 AM

The pedal getting higher, when pumped with the engine off, is all right and happens due to vacuum being depleted from the brake booster. When the engine is started with the brake pedal depressed, the pedal should sink a bit further. The brake booster gets evacuated again and helps to push the pedal.

With all the repairs that you already did, the master cylinder does sound like the next thing to do. Seen the same problem on a different Toyota, but that was the rear brake shoe adjustment. If the shoes are not extended properly, a lot of brake fluid goes into the rear cylinders, making the pedal drop low.

If the car sat for so long, I would imagine the seals in the master cylinder, or anywhere else for that matter, did not take it very well. I would expect the pedal to KEEP dropping slowly though, if the master cylinder was weak.

But before you go at the master cylinder perhaps you could try to adjust the rear shoes so that they pretty much cannot move with the drums partially installed. Just to keep the rear shoes from moving. Then see if the pedal height is acceptable. If it is, then this would indicate that the master cylinder is in fact all right.
Thing is, the drum's inner diameter where the shoes ride, could be a bit larger than the diameter right along the edge which the shoes cannot exceed in order to install the drum. So if the shoes are extended as much as possible while still allowing to put the drum on, they could have quite a bit of play left, once inside the drum.
The self-ajustment mechanism should eventually take care of that, but even if it does, I would prefer to replace a drum with that kind of wear.

zppeacock · 01-02-2011, 01:01 PM

I will try adjust the rear shoes so the drums barely move but I think I will replaced the rear hardware and the drums as they are rusted pretty bad.

speedy25 · 01-02-2011, 08:56 PM

The typical problem is the shoe to drum clearance in the rear causing low pedal.

When you get new drums or turn the old ones check out some advice in another thread-

Fitting Rear Shoes

My pedal sits nice and high.

-SP

zppeacock · 01-02-2011, 09:15 PM

Thanks for the tip, I will check that out when my new drums get here.

I went ahead and installed the New not rebuilt master since it came with the car when I got it. I didn't get time to bleed the lines at the wheels but I did bench bleed the master. The pedal is still very very low but the little travel it has is firmer now then with the old master.

I have new drums on their way from rockauto as they were on closeout and saved me some money.