Why won't my brake pedal return quick?

[Diesel]

A little background on my truck. When I bought the truck the brakes were 100% shot. I installed a new booster, master, front calipers and pads. Now I have good brakes BUT the pedal returns slow. So I am thinking I either don't have enough vacuum or my brake lines are swollen inside and hold fluid at the calipers. They are most likely the original lines so it is possible that they are acting as a diaphragm. Should I replace the two front rubber lines and the one rear rubber line and see if that fixes it?

[dazedandconfused]

I personally would since they are 20 years old.

[ellis93]

Been thinking on this and I'd say no. The reason is that if the hoses held pressure on the calipers and wheel cylinders they'd not release. This would lead to super hot wheels, warped rotors and smoking brake pads or shoes. Like D and C said they are 20yrs old and could stand to be replaced thou.
The way parts are thies days I'd say maybe try the master again or maybe the proportioning valve. Either way this will be a roll of the dice.

[Diesel]

Thanks guys. I'll start with the rubber hoses. Does your pedal return quick after depressing it?

[Gots_a_sol]

Mine is slow to return as well. I don't remember it being this way until I converted to hydro-boost though.

[Richie O]

The fluid does not need to return for the pedal to come back up. If it did you would not be able to bleed the brakes. ( makes sense in my pea brain anyway )

[ellis93]

The fluid does not need to return for the pedal to come back up. If it did you would not be able to bleed the brakes. ( makes sense in my pea brain anyway )

As I can't speak for your brain, I can say that I think you'd be correct. There is a spring inside the master as well as the booster. I would think in one or the other is the problem. Reason for me suggesting that the master be tried first is because it would be the easiest to change out.

[Diesel]

I see. So its probably not the brake lines I take it?

[ellis93]

Probably not.

[Mark Nixon]

How FAR does your pedal go to the floor before you have brakes?
If it's going 3/4 of the way to the floor before they apply, naturally it'll take some time for the pedal to return, the further down, the worse the return rate.

A bad vacuum booster is normally accompanied by hard brakes that won't apply quickly and will usually have a hissing noise as vacuum escapes the booster.
It also provides a false "hard pedal" on bad, or mis-adjusted brakes.

The MOUSECHARGER has that issue, needs the booster replaced.

Mark.

[Diesel]

Brakes come on within an inch of pushing down. I think the problem is with the lines and not the master. Booster doesn't hiss and pedal isn't difficult. I'll do all 3 rubber lines and if it still acts up then it will get another master. The current master is a rebuilt A1-Cardone. So there are only 3 rubber lines, right?

[Mark Nixon]

Yes, only the 3.

Mark.

[cougar]

Thanks, this has been helpful troubleshooting my 92. Slow return is one of my symptoms and I was thinking booster. I still am because of the "effort" required on the brakes using my 2 trucks as comparison. My 91, a 5 speed has a firm hard peddle with great braking abilities while my 92, an auto has a squishy peddle and not so impressive and a little unnerving braking ability. The master cylinder had been replaced (several times) and I still question its quality. The ABS valve may also be bad.

[Diesel]

Thanks, this has been helpful troubleshooting my 92. Slow return is one of my symptoms and I was thinking booster. I still am because of the "effort" required on the brakes using my 2 trucks as comparison. My 91, a 5 speed has a firm hard peddle with great braking abilities while my 92, an auto has a squishy peddle and not so impressive and a little unnerving braking ability. The master cylinder had been replaced (several times) and I still question its quality. The ABS valve may also be bad.

So Cougar you've replaced the master a few times with the same results but you haven't replaced the booster yet? I have replaced the master and booster but the booster seemed a suspect rebuild. I have replaced everything in the brakes except the rear rubber hose and still the pedal is like a manual lever. Down to stop and then pick back up to return. I think its my booster because if I let it sit at idle for a while vacuum builds up it seems and the brakes are real high and strong.

[cougar]

Sense my last reply, I put on a new master cylinder. The others were remans and were junk. The brakes have improved greatly, but are still not 100%. I have an ABS hydro unit on order and I'm hoping that will get rid of the squishies. Then on from there.