Too much brake pedal travel

[iinca]

Just finished replacing the entire braking system and now I have great brakes.

Nice firm pedal and you can't pump them up one iota. Cold or hot..

 

 

All new>

 

Rotors/Drums

Wheel cylinders

Resivoir

Pads/Shoes

Calipers

Soft lines

Hard Lines

Master'

Booster

Fluid

 

I put them through a few heat cycles and they are probably the best they can be.

Yet I still have a way too much PEDAL TRAVEL!  Like half way down. It's kinds dangerous and really annoying

 

And yes the E brakes are fully adjusted.

 

..I thought maybe adjusting the brake rod might help but something tells me that 

will only adjust the pedal height...OR will that help? I know getting to that top lock nut on the rod is a nightmare.

If I can avoid it that would be fine by me

 

 Seems like there should be an easy way to take that extra "mechanical"

pedal travel out.

 

*Note : I bench bled the Master and used a power bleeder on the system.

 

*I never ask questions. I search and learn but this one has me perplexed

 

 

Edited July 23, 2019 by iinca

[dlacey]

What's it like with handbrake on? If different then it's rear shoes adj

[Hans]

I would revisit rear brake adjustment. Also, did you get the right sequence for bleeding calipers? Sometimes it takes the two person up-down bleeding to finish it off.

[Brandon]

I’d try bleeding the whole system again.  Otherwise I’d say one of those new parts is possibly bad.

Edited July 24, 2019 by Brandon

[Hans]

You are aware of the caliper bleeding sequence? Just checking.... And you did adjust the rears with the two bolt heads?

['76mintgrün'02]

3 minutes ago, Hans said:

the caliper bleeding sequence?

 

which is, "you I owe"

 

(upper inner outer)

[Einspritz]

Wear in the linkage can account for a lot of pedal slop.

 

With all new pivots, clevis' and pins, the slop should be about 2 pedal thicknesses, no more.

 

Since the pedal length is about 400 mm, any very small slo p at each of the  pivots will be amplified. You can't adjust  and don't need to change the rod lengths, only for making the pedal the same as the clutch.

 

Check or refurbish accounting for wear.

 

I think you still have air in the system.

 

 

[Hans]

2 hours ago, Einspritz said:

Wear in the linkage can account for a lot of pedal slop.

 

With all new pivots, clevis' and pins, the slop should be about 2 pedal thicknesses, no more.

 

Since the pedal length is about 400 mm, any very small slo p at each of the  pivots will be amplified. You can't adjust  and don't need to change the rod lengths, only for making the pedal the same as the clutch.

 

Check or refurbish accounting for wear.

 

I think you still have air in the system.

 

 

Good point. Do those push rods have the plastic bushings that sit in the pin hole?

[iinca]

It's more than pivot points. My pedal box 'looks and feels pretty good..not sure if it was rebuilt  somewhere in it's  recent past. It's one of the things I didn't do in my rebuild 'cause it feels pretty smooth.

 

No difference with the E Brake on

 

I'm gonna go through the bleed' again for starters

 

I SHOULD have the best g*damn brakes of any 2002 I've ever owned lol. 

 

BUT besides bleeding it's more likely its' a shitty master..or those Roger's tii calipers. This issue is the LAST thing on my 100% mechanical rebuild so I'm gonna be patient.

 

One can't rule out anything when the parts aren't all OE

 

I will say for the record the brake lines Andrew made me are insanely awesome.

Edited July 23, 2019 by iinca

[Preyupy]

Just because I have seen it more than once,  when you installed the calipers did you get them on the correct sides?  The bleed screws point UP.  Not to be a jerk but I have seen at least 3 people I thought were much better mechanics than that put them on the wrong sides with the bleeders pointed down. 

[iinca]

I was aware of that 20 years ago...but who knows I better check again lol

 

like I said everything is suspect at this point. I'm in a f*ck it I'm gonna fix this if it kills me mode

 

thanks I'll check that right now.

 

 

Edited July 23, 2019 by iinca

[Mike Self]

A poorly performing brake booster can lengthen pedal travel...have you carefully inspected the booster and its supply hoses--especially the little short one that goes between the one-way valve and the manifold.  It's under a constant side load and will eventually crack.  The same hose for an E21 has a bend molded in so will last much longer...

 

mike

[iinca]

bleeders are pointed up...damn 

 

back out to the shop to check booster hoses...

Edited July 23, 2019 by iinca

[iinca]

Ok that hose looks to be fresh but I think I'll get some new Cohline' vacuum hose and totally eliminate that possibility

Edited July 23, 2019 by iinca

[uai]

I'd check the Residual Pressure Valve (had to look up the english term) in the master cylinder.

The symptom you're describing fits exactly a faulty one.

This valve will keep some pressure in the drum brake circuit when not used.

Edited July 23, 2019 by uai