1982 Excessive Brake Pedal Travel

[CJ7Jeepers]

My 1982 CJ7 ’s brake pedal has a very long travel – the brakes finally kick in when the brake pedal is just about to the floor, and even then they seem to be at only 75% capacity. I need some help finding what the problem is.

My Jeep has been sitting unused for the past 5 years, and this summer I’ve been getting it drivable again. When I got to the brakes, the pedal went right to the floor with no resistance. Since all the bleeder screws were frozen in place I replaced almost everything – the master cylinder, the front brake calipers, and the rear brake cylinders. I also replaced all the pins, springs, and adjusters in the rear drum brakes. The brakes are not power brakes so there is no booster or anything like that.

I did not replace the shoes or pads because they were new when I parked the Jeep five years ago and they still had plenty of thickness. I did not replace the brake lines since they are not leaking. I also did not replace the proportioning valve since there was no indication it was a problem – and it’s kind of pricey.

Oh, and I have bled and bled each brake line, on two separate occasions – I used close to a whole quart of brake fluid, well beyond the point where there were no air bubbles and the fluid was clear. I have adjusted the rear brake adjusters so they’re set properly,

Does anyone know why the brake pedal would be so soft? Is the master cylinder out of whack?

 

[Cheepjeep85]

Its possible that there is still air in the lines more likely in the calipers. It is also possible you got a bad master cylinder especially if you bought a remaned one, its happened to me with my jeep. Id try using a vaccum bleeder, they can be rented at most auot parts stores.

Droooiiddd 2

 

[CJ7Jeepers]

Yeah, all these parts are re-manufactured.

I mean, for there to be that much squish in my brake pedal the fluid has to be going somewhere, right? It doesn't compress. And it's not leaking out. Either there still is air somewhere, or the fluid is backflowing past the valves in the master cylinder back in to the reservoir.

Could there be something else I'm missing?

 

[Purple77CJ7]

Sounds like there is still air in the system.

 

[Cheepjeep85]

after all of the bleeding you have done, i would highly suspect the remaned master cylinder.

 

[CJ7Jeepers]

Okay, maybe I did a DUH - I should have bench-bled this master cylinder first, right? Well I didn't even think of it. I just mounted it on the firewall, hooked up the brake lines, and started bleeding the lines themselves. I'm thinking this might be the problem.

If I disconnect the lines and plug the two ports, I can bench-bleed the MC right there on the firewall, can't I?

 

[Cheepjeep85]

Yes

Droooiiddd 2

 

[mylittlecj5]

When I put the YJ master cylinder on my Jeep, I mounted it on the firewall (some fabrication required) and had a set of soft lines made up for it. I used them to "bench-bleed" the MC on the jeep by sticking the open ends of the soft lines in a container of fluid and pumping the pedal. Bled them out perfectly.

 

[Trailpunisher82]

So did the bench bleeding of the MC help? My 82 CJ7 has the same problem. Previous owner replaced the MC and I have bled the brakes twice so far and the problem is still the same. Also I have read a "Tip" from 4WD parts and they say on a CJ that you have to bled the front brakes first then the rear ones. Anyone heard of that?

 

[hole]

When I put the lift with longer brake lines I had trouble at first because I was trying to bleed the rears first.http://www.jeep-cj.com/forums/f19/what-proper-way-12118/ After reading this thread I tried fronts first, then rears, then fronts, and the 8 has never stopped so well.