Hard to diagnose brake problem

[Fester's Quest]

Hi all, i've been having a brake issue for the last 6 months because i haven't been able to figure out whats causing it.

I thought it was the master cylinder, replaced that, didn't change anything. Thought it was the driver's side caliper, replaced that, didn't change anything.

When you hit the brakes, sometimes it has good pressure, sometimes it has almost zero pressure, and sometimes medium pressure. When the pedal sinks to the floor, and you press as hard as you can to stop, you can feel that the right side of the car is doing all the braking. Also when it sinks to the floor, you can feel the warped rotor on the left side wobble, but when the pedal has pressure, there is no rotor wobble felt at all and the car stops smooth & fine.

If i bleed the driver's side caliper, the brakes will be alot better for awhile ( pedal still sinks to the floor occasionally ) but then progressively starts to loose pressure more often.

The only thing i can figure is it's gotta be a problem with the line, but it doesn't leak any brake fluid, so i don't have any clue what it could be.

Are there any check valves in the front brake lines ?

[FestYboy]

no check valves. you may be sucking air in from one of the fittings in the system and you might want to look over the rear brakes while you're at it.

[crazyrog17]

Hard to diagnose brake problem

My girlfriends Festiva had the wackiest brakes... I tried everything and couldn't find leaks. It ended up being a bad rear wheel cylinder. Take a look at the rear end and make sure those little boots aren't torn and leaking in the brake drum.

[Fester's Quest]

My girlfriends Festiva had the wackiest brakes... I tried everything and couldn't find leaks. It ended up being a bad rear wheel cylinder. Take a look at the rear end and make sure those little boots aren't torn and leaking in the brake drum.

Good call, I'll check out the rear wheel cylinders tomorrow.



Does anybody know how the brakes are sorted out by that little aluminum splitter block that the two lines run into and the 4 come out to each wheel ? Are the two brake lines from the master cylinder split into front and rear brakes, or left to right side brakes from the splitter ? Because then that would make sense why my front brakes would give out from a bad wheel cylinder if it was sorted by left to right instead of front to rear.

[Fester's Quest]

no check valves. you may be sucking air in from one of the fittings in the system and you might want to look over the rear brakes while you're at it.

I'm definitely worried that i may have to break loose ( without breaking ) all the brake fittings and seal them with thread tape.

[FestYboy]

no, brake fluid will eat that stuff up. the fittings are designed to seal dry.

[Movin]

That is not where the brake fluid is sealed. ( i may have to break loose ( without breaking ) all the brake fittings and seal them with thread tape.)

The end of the tubing has a flared connection. That has to be clean, no scraped or gouges, rust free. The threads have to be clean enough to compress
the two angled parts together. Tape may make removal easier next time but it is intended for pipe threads that actually do seal fluid or gas inside.

Whups ^^^ stated so much more to the point, thanks festYboy!

[Fester's Quest]

Finish Him ! Noobality !!!

I suck at brake problems...

[FestYboy]

hahaha

[rbrown]

Good call, I'll check out the rear wheel cylinders tomorrow.



Does anybody know how the brakes are sorted out by that little aluminum splitter block that the two lines run into and the 4 come out to each wheel ? Are the two brake lines from the master cylinder split into front and rear brakes, or left to right side brakes from the splitter ? Because then that would make sense why my front brakes would give out from a bad wheel cylinder if it was sorted by left to right instead of front to rear.

Look at the splitter. It has F and R on it.
Do you have a stock master cylinder on here?

[FestYboy]

they are split cross wise, LF and RR are on one circuit and RF and LR are on the other.

[Fester's Quest]

Look at the splitter. It has F and R on it.
Do you have a stock master cylinder on here?

Oh, i see it now. mine was very dirty, my bad.

Looks like my problem is probably a driver's side wheel cylinder.

Not sure about the brake master, it's a reman from a local parts store.

[Fester's Quest]

they are split cross wise, LF and RR are on one circuit and RF and LR are on the other.

Oh ! So then passenger side wheel cylinder... i hate working on brakes :gritteeth:

[WmWatt]

Try pumping the brake pedal before braking.

[Fester's Quest]

Try pumping the brake pedal before braking.

That helps, but only sometimes.

I went ahead and ordered some new rear wheel cylinders. $12 each at O' Reillys