I have a 69 fj40, bleeding the brakes and still have soft pedal. I put new cylinders on, new master cylinder, which was bench bled and now when you pump up the brakes the master cylinder is either getting air and or brake oil bubbling back into it?? What is the problem, air still in the system??? Any help would be great, thanks.
Need brake help (1 Viewer)
- Thread starter bosscat800
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Don't even bother trying to bleed them before you get the cylinders adjusted. RTFM.
What's the proper wheel cylinder adjustment then? I pushed the shoes against the drums then backed off 5 or 10 clicks... Should it be less?
My issue is not pumping up at all... I thought I bleed all the air out (although I did it alone I believe that my way is effective and I've utilised it on many diffent vehicles, just not one with 8 wheel cyl's)
I can pump it about 6 or 8 times and the pedal comes up about an inch but with any more pressure I can still push it to the floor.
Think I should adjust the shoes out more then do it again?
FE
My issue is not pumping up at all... I thought I bleed all the air out (although I did it alone I believe that my way is effective and I've utilised it on many diffent vehicles, just not one with 8 wheel cyl's)
I can pump it about 6 or 8 times and the pedal comes up about an inch but with any more pressure I can still push it to the floor.
Think I should adjust the shoes out more then do it again?
FE
When I have done my drum brakes, I adjust out to where the wheel drags slightly. I give the wheel a spin and when it turns about 1 revolution, I feel I have the brakes adjusted about right. This usually equates to backing off 2-3 clicks. The shoes will rub for a while, but it seems to give a good brake feel. IMO, 5-10 clicks backing off is way too much.
Good luck!
John McVicker
SILVER Star
Easy way to learn how to adjust your wheel cyls:
Go to 'technial links' @ top of this page, go to 'axel/drive train', then go to Jeff Zepp's 'drum brake adj' Excellent write up.
This is how I do it: Adjust 1 cly @ a time until the wheel won't turn, then back off only 1 maybe 2 clicks, turn the wheel, then do the same on the other cly on same wheel( if you have 2 cyl per wheel), then do the other wheel on same axle. Then drive it (b-4 doing the other axle) make any additional adjs. as necessary, pulling to on side or needing to tightening/loosening. Drive it a couple of miles, do some hard stops,making sure it doesn't pull to one side.
Then to determine if they are too tight, let the brakes cool down, drive it several more miles w/o using the brakes at all , coast to a stop & hop out to touch the wheels/drums. Warm is OK, too hot to touch is not good & back off 1 click, test drive again. Then repeat for the other axle. Remember to not back off too much and a warm drum(not hot) is OK. They will wear in just fine. If you do it correctly, these drum brakes can/do work great. But it can be time consuming getting them just right...but can be done.
HTH, John
Well, like others said, I think "5 or 10 clicks" is too much. I leave mine just slightly touching, but not enough to get hot. When adjusting, it's important to occasionally pump up the brakes to seat the shoe against the drum or else you'll be adjusting one side of the shoe into the drum and think that you're rubbing, but if it's not centered, the adjustment is moot.
To address your current problem, it sound like you either still have air in the system or you have a bad flex line. I'm assuming that you replaced all of the rubber hoses between the frame and axles right? Even on maladjusted drums, you should be able to pump up the pedal and stand on it without it moving. It definitely shouldn't be going to the floor.
ive always had the best luck with the 2 person method like poser mentioned, with all those bleeders it would be hard to do it any other way IMHO
John McVicker
SILVER Star
I agree, 2 man system is easiest. But it can be easly done if you are alone & have some type of vacuum pump. My mity-vac works great. You can also buy a dedicated brake only vac pump @ most auto parts/Sears for $10-20.
From his discription however, my guess is he just needs to adjust the cyls a bit( alot) tighter. He should be good.
John McVicker
I was “bench bleeding” my new brake master cylinder inside my truck last night… the rear outlet did not pump any brake fluid back up into the cup like the front one did. I pumped the pedal probably about 15 times.. what am I doing wrong? Am I supposed to bench bleed each end separately? How?
