In Need of Help! Brake booster lines

[dropaduece]

Dear Fellow Members.

I attempted to move my m35a2 out of the driveway after sitting for about 6 months. In this six months I have been working on converting it to a 4x4.

It started up fine yet when I tried to put it in gear it could barely get out of its own way. It seems like the front wheels are locking up and the back tires are just spinning.

I completely rebuilt the braking system, new master cylinder, rebuilt booster, new air lines, new brake pads, new air lines.

I am wondering if I messed up somewhere. When I had the truck in the air I adjusted the brake cambers to get the pads closer to the drum.

I opened the air bleed valve all the ay and drained all the air out, thinking that the booster might be sticking, yet didnt seem to make a difference.

I could really use some advice. After spending thousands upon thousands on this project I get to the end and have this going on. I dont know what to do next.

Seth

 

[timntrucks]

emergency brake off? it has happened before. or might just be one wheel clyinder locked up

 

[dropaduece]

Emergency brake is off, atleast the handle is down. I had replaced the emergency brake pads as well. The back tires seem to be turning fine, yet maybe the e-brake is dragging a little bit.

I just went out there and backed the pads all the way off the drums and still nothing.

Maybe the next thing I can do is disconnect the air line completely from the booster and see if I get any change. Maybe the compressor is still building up enough air even with the drain valve open.

I replaced all the wheel cylinder when I did the pads. I just dont know.

Seth

 

[timntrucks]

something sure is binding up. ill be thinking what all could have happened .

 

[jimm1009]

sticking brakes

I'm not sure why it would hapen but try letting any trapped pressure out of the bleeder ports on both front wheel cylinders.
Possible you have one with pressure built up and stuck that way. Could be a defective new wheel cylinder that is sticking.
Can't hurt anything but leak a little dot 5 on the ground.

Also try backing up just a little rather pulling forward once pressure (if any) is bled off.
I had a new one stick once too for no known reason.

Jim

 

[dmetalmiki]

heres a thought

Take the FRONT propshaft OFF! then give it a try..I have a feeling it's possible you might have jiggered" the sprags in the modification. let us know if this helps,,it takes little time and elliminates drive train prbs. leaving you with the obviouse conclusion that the FRONT BRAKES are hanging up. (if the propshaft removal dunt cure it ) the fall back is unlikely to be the propshaft brake? (the rears woud'nt be free wun they?? just a thought or two...keep us informed WE WILL get yer goin!!

 

[dropaduece]

Guys went out again and completely disconnected the main air line from the booster. It seemed to work and I was able to take a drive around the block, yet barely had any brakes.

Do you think if I had the main air source comming into the brake booster in a wrong port it would do this. This was always an issue that I was worried about from the beginning.

Is anyone familiar with the booster port identification?

I could send a picture of my booster and lines and label where they are all going. Maybe I have them hooked up wrong.

Seth

 

[dropaduece]

Front propshaft off? Is that the same as the front drive shaft ( the shaft running from the transfer case to the front axle?

What are sprags?

I very well could have screwed something up, this was my first conversion yet everything was going smoothly until now.

I shortened the rear drive shaft, had it balanced and welded back up. It slid back into the slip joint fine.

Seth

 

[dropaduece]

M35a2 brake booster lines

Dear Fellow Members,

After some head ache I think I figured out why my brakes were locking up.

I believe I have the air lines comming to the brake booster all messed up.

Is there any one that could tell me which lines need to go where.

I have 4 line that I need to identify.

Main air line from comressor
Secondary air line from booster to truck accessories
Trailer air brake line
Exhaust line

Seth

 

[wdbtchr]

That was my first thought that the sprag might have gotten bound up. If you turned the front wheel while it was off the ground could the sprag have locked up?

For dropaduce, the sprags are what engage to put power to the front axle when the rear wheel slips aproximately 1 1/2 % faster than the front wheels. If the vehicle is in a forward gear and you roll back or visa-versa, it can cause the drive system to bind up and cause the truck to wheel hop violently. The cure is to jack one front wheel off the ground to release the strain, but watch out for the wheel to spin when it comes free from the ground, stand clear.

 

[dropaduece]

Thanks for the info about the sprags.

I think it was a combination between the sprags and the booster hooked up wrong.

So all I have to do is jack the front end up and it will release the tension and the wheels will spin free?

Do you happen to be familar with the brake booster lines?

Seth

 

[doghead]

Do not start a new thread, when you already have one going on this problem? Look at the TM.
TM 9-2320-361-20 Chapter 8

 

[dropaduece]

Guys I could really use some help still.

It is not the sprags. I jacked the front up just to make sure.

Airpac lines are all plumbed up right.

I then thought it might be because I used a remote resevoir yet I made sure mine was vented.

So where does the leave me. Did I rebuild the air pac wrong?

When I first tried to move the truck I could clearly hear the exhaust valve piss everytime I released the brake pedal.

Now I dont hear anything.

I have read a lot of posts about the master cylinder compensator port?

Any help would greatly be apprecited.

Seth

 

[cranetruck]

Recheck the airpak plumbing, if the "breather" line in the image below is blocked, the pressure will not release.
Yeah, right click on the image and "Open link in new window" for full resolution.....