Brakewhisperer Services Needed-Where's that air coming from?

KenInGA · Post by **KenInGA** » Mon May 26, 2008 5:25 pm

Evening boys and girls-

Got home from the Roswell Remembers Memorial Day Ceremony and got busy. Pulled the left rear and replaced the last wheel cylinder. I had replaced the other three and the master cylinder last fall or sometime around there. Everything went fine. Note- We have not adjusted the brakes yet, as we were waiting until we got this last wheel cylinder on.

Then we went to bleed the brakes. Started on the L R. Lotsa air, but it cleared up. Okay, whatever. On to the R R. Lotsa air. 1/2 gallon of brake fluid later, lotsa air in the fluid. And there's no pedal, even if you try and pump em up. FWIW, we're manually bleeding the brakes here. Dad on the brake pedal and keeping an eye on the level in the Master Cylinder, yours truly manning the wheel cylinder.

At the bleeder valve, when you push down on the pedal, it seems like some brake fluid seeps out around it. I'm not sure. I thought it was just coming out around the hose where its on the nipple of the bleeder valve. But I look at the other wheel I just did, and not nearly as much brakefluid. I'm not talking a lot, but some. Could it be sucking air into the system from right there, either at the bleeder valve and/or the brass junction block? Or is there another leak somewhere... all of the wheel cylinders are fine, no leaks anywhere on them, all the bleeder valves tightened up nicely. Any ideas? Thanks for your help

Ken

Lifer · Post by **Lifer** » Mon May 26, 2008 7:35 pm

It's possible that you have a defective bleeder valve. The shells are rather thin in the thread area, and they can crack if tightened too much or if hit by a solid object such as a rock...or a hammer. They're cheap and easy to replace, however. Just unscrew the old one all the way out and screw a new one in. Napa, et al, will have them.

Dicktater · Post by **Dicktater** » Mon May 26, 2008 7:51 pm

Did you replace the copper crush washers at the wheel cylinder?

KenInGA · Post by **KenInGA** » Mon May 26, 2008 8:10 pm

Lifer- Thanks, I'll check on that

Dicktater- only one of them, the one between the junction block and the wheel cylinder, but not the one between that block and the bolt that goes through it. I'll get one and replace it.

Lifer · Post by **Lifer** » Tue May 27, 2008 3:40 am

You'd better get 2 of the crush washers. Once you've crunched it once, it should be replaced if removed again.

KenInGA · Post by **KenInGA** » Tue May 27, 2008 6:27 am

Okay. That's good to know! Thanks!

g741 · Post by **g741** » Fri May 30, 2008 4:56 am

Hello: Seems like you may have solved the problem. But, on these trucks you will never have a good solid pedal until the brakes have been properly adjusted. This means adjusting both the lower and upper adjusters. Good luck with it. The M37 stops well with the original stock brakes as long as they are properly installed and adjusted.

Juan · Post by **Juan** » Sat May 31, 2008 10:12 am

Amen,
Adjusting is the name of the game with the m37 brakes.

KenInGA · Post by **KenInGA** » Tue Jun 03, 2008 3:35 pm

g741 wrote:Hello: Seems like you may have solved the problem. But, on these trucks you will never have a good solid pedal until the brakes have been properly adjusted. This means adjusting both the lower and upper adjusters. Good luck with it. The M37 stops well with the original stock brakes as long as they are properly installed and adjusted.

Amen. I adjusted the brakes on the wheel where I had just put the wheel cylinder on. I waited a day (just because I had a load of other things to do) and used my newly thrown-together power bleeder, and lo and behold! No more air in the lines, just brake fluid. And I have some pedal, too...

Thanks so much guys!
Ken