Braking issues with new truck.

[BoostJack]

Im having some braking issues with the truck I just picked up. I replaced the air pack after reading about how common it is to go bad. It appears to be functioning now. Bled the entire system and holly crap, Ive seen some bad fluid but Ive never seen fluid go that rotten. Im almost certain it was mostly original fluid or the wrong stuff was put inside and it broke down dramatically. The PO had replaced the master cylinder and it looks to be either reman or brand new; it also appears that it may be leaking or that I need to tighten the crap out of the cap. I do have a reservoir kit from big mikes coming in soon. Basically, If i press the pedal all the way down, it goes almost straight to the floor. I can pump it up but the pedal eventually becomes beyond pushable until I let off, as it was before but with no form of braking whatsoever. I dont think I have any air left in the system unless its not fully bled at the air pack. Since I changed the air pack and bled the entire system down, its much better and feels like it might actually stop eventually. Any ideas? might the master cylinder assembly be causing an issue? Might this be a wheel cylinder issue? I have yet to make any shoe-drum adjustments; it doesnt make sense that all would be that far out of spec to cause a pedal issue.

 

[Jeepsinker]

Sounds like you still have air in the lines somewhere. You need to pull the drums anyway and check the wheel cylinders, so you may as well adjust the shoes up.

 

[BoostJack]

Looks like Ill wait till the remote reservoir gets in so I can hook a power bleeder up.

 

[cattlerepairman]

If your master cylinder cap is leaking, make sure you have the flat plastic washer on the cap that seals it. If that is missing, a flat washer for a 1 1/4 (I think; better measure) sewer trap from your home hardware store is an almost exact fit.
The cap needs to seal in order for the pressure bleeder and remote reservoir to work. Ask me how I know that!

Also, when you bleed the brakes, you need to start with the bleeder on the hydraulic side of the air pack and then move on to the wheel cylinders. Any fluid at all seeping out of the brake drums? I'd probably pull the brake drums, regardless, check the condition of the wheel cylinders, linings and adjust the shoes as per TM.

 

[BoostJack]

If your master cylinder cap is leaking, make sure you have the flat plastic washer on the cap that seals it. If that is missing, a flat washer for a 1 1/4 (I think; better measure) sewer trap from your home hardware store is an almost exact fit.
The cap needs to seal in order for the pressure bleeder and remote reservoir to work. Ask me how I know that!

Good point! The plastic washer is not in place and from the looks of the metal to metal contact, it hasnt been in there for a while.

Also, when you bleed the brakes, you need to start with the bleeder on the hydraulic side of the air pack and then move on to the wheel cylinders. Any fluid at all seeping out of the brake drums? I'd probably pull the brake drums, regardless, check the condition of the wheel cylinders, linings and adjust the shoes as per TM.

I have not pulled the drums yet but I see no signs from the outside that they are leaking. I should have the reservoir kit in tomorrow or Sat. and I picked up everything needed to make my bleeder. Ill definitely be pulling the drums soon to inspect the brakes. Ive already got to do the grease seals on the front axle so I might as well take care of some PM items.

 

[welldigger]

You won't always see a leaking wheel cylinder from the outside.

Try re bleeding the brakes first. Start at the air pak. Then go to the right rear most wheel. Then the left wheel. Then the right middle wheel. Then left middle.

Then go to the left front and then right front. The front axle is in backwards order of the rears. Though it probably won't matter a whole lot which front wheel you start with.

You basically want to start the sequence at the furthest away wheel cylinder from the master cylinder.

Also, pull the rubber boot back on the master cylinder and check for fluid leaking. I know you said it looks new but it only takes a second to check.

I also suggest checking every wheel cylinder.

 

[gimpyrobb]

Why do you say you need to do the "grease seals" on the front? There is an inner oil seal, boot, and spline cap. I don't remember the front needing grease seals.

Edit, yeah, i think there is a seal to keep the rear bearing grease away from the brakes. Carry on!

 

[welldigger]

Why do you say you need to do the "grease seals" on the front? There is an inner oil seal, boot, and spline cap. I don't remember the front needing grease seals.

Edit, yeah, i think there is a seal to keep the rear bearing grease away from the brakes. Carry on!

Ya the front has an inner grease seal on the spindle. The outer seal is optional on the front.

 

[BoostJack]

Why do you say you need to do the "grease seals" on the front? There is an inner oil seal, boot, and spline cap. I don't remember the front needing grease seals.


By grease seal I meant grease boot. Sorry, fast typing while in the middle of other work. There are tears in both front boots.

 

[w3azel]

That sounds a little extreme for just having air in the lines. I drove my M36 that needed the brakes bleed but I could build and hold pressure. Also these brakes when bled and set properly will want to through you through the windshield. Some guys dog on them but after I went through the brakes and bleed them completely . I can't get the pedal more then half way down and everything is locked up. Also wish I could help you out in person but I'm leaving Saturday evening and tied up going through my truck to get it ready for a long trip.

 

[shenkmen]

Basically, If i press the pedal all the way down, it goes almost straight to the floor. I can pump it up but the pedal eventually becomes beyond pushable until I let off, as it was before but with no form of braking whatsoever. I dont think I have any air left in the system unless its not fully bled at the air pack. Since I changed the air pack and bled the entire system down, its much better and feels like it might actually stop eventually.

If you can still make the pedal stiff by pumping the pedal your brakes need adjustment. Adjusting the brakes will remove this issue on a properly bled system. There's a lot of info on this site about it.

 

[BoostJack]

Hey w3azel, when you make it back into town feel free to give me a shout. I pm'd you on your location in fayetteville.

 

[Tinwoodsman]

If you have any problems at all and plan to install a remote reservoir, then why not just go through the whole system, particularly adjusting the shoes. That way you know you have done it right and do not have to rely on the original owner or anyone else.