M-38 Brake Adjustment Advice

dv3468 · Post by **dv3468** » Fri Mar 16, 2007 10:36 am

Gentlemen: The brakes shoes on my M-38 need adjusting. The pedal is a little low when I step on brakes. The master cylinder is new and I bled the brake lines four times with no improvement on stopping ability. I have the universal jeep manual which explains how to adjust the brake escentrics.

But does anyone know of any "tricks" or suggestions before I attempt an adjustment. Thanks, Dennis.

Post by **wesk** » Fri Mar 16, 2007 9:39 pm

When you say the pedal is low are you referencing travel or softness?

Have you confirmed the condition of the 4 wheel cylinders and the linings/drums? That is to say does the arch of the shoes match the radius of the drums and are the drums and shoes clean and dry.

You installed a new master cylinder. Did you adjust pedal travel? Did you bench bleed the master cylinder? Did you bleed the brake light switch cavity?

Ryan · Post by **Ryan** » Sat Mar 17, 2007 7:33 am

I have a question. When I replaced my brake system on my M38 I did not bench bleed my master cylinder. I put everything together and bled the brakes then. My jeep seems to be stopping fine. Will I have anything to worry about from not bench bleeding the master cyl?

Post by **wesk** » Sat Mar 17, 2007 8:32 am

Probably not. Some master cylinders do to there mounting need the bench bleeding done first. It always makes it easier to bleed the system on a new master cylinder install if you bench bleed it first. The only way to get any air trapped at the pressure swutch is to bleed the switch itself by loosening it just as you would a bleeder screw.

dv3468 · Post by **dv3468** » Sat Mar 17, 2007 1:53 pm

Wes: This is why I ask the experts. When I restored my jeep, I noticed that all four brake cylinders were new and the front brake lines were new. I never pulled the drums off to inspect the drums/shoes. Because I "Assumed" that they should be good since the brake cylinders were new. Mistake #1. When I replaced the master cylinder, I did not bench bled it, I installed it with a new brake lite switch that I filled with fluid and the bled the system. Mistake #2. I did adjust the brake pedal travel though, (#1 for me!) I am a little unsure about pulling off the drums, since I don't have a hub puller and I never did a brake job before. As far as the pedal travel; if I step on the brake pedal with slow pressure it goes down 2/3 of the way to the floor board before it is stopped by the pressure from the master cylinder. If I pump the pedal, it stops about 1/2 way down. Thats why I keep bleeding the brakes, because I thought there might be air in the lines. Thanks agin, Dennis.

P.S. I think I know what your response will be. "Find a good mechanic"

Regards, as usual, Dennis.

Post by **wesk** » Sat Mar 17, 2007 3:14 pm

Sounds like you still have air in the system. Anytime the first push gives you less pedal than the next pump up you have air.

If everything was just recently assembled then it shouldn't be too difficult to pull the drums. Remember you will not need to seperate the hubs from the drums. Just the hub/drum assembly from the axle.

dv3468 · Post by **dv3468** » Sat Mar 17, 2007 3:31 pm

Thank you for getting back to me so quickly Wes. Happy St. Patty's Day to all.

Regards, Dennis