New Wheel Cylinder Issues

[USMC 00-08]

I am still trying to solve this issue and prefer to do it once. After jasonjc mentioned having problems with the Napa 14451 cups, it caused me to step back and look some more.

Here are the two seals side by side. The outer lip of the Napa seal is thicker and I can see why this may have caused jasonjc the problem he had and one that I would like to avoid.


Here are the two seals on each of the different kinds of pistons.


I don't know if I should use the new pistons with Napa seals, the old pistons with the seals out of the new wheel cylinders or use the Napa seals on the old pistons in the new wheel cylinders.

I would greatly appreciate any insight here. Especially if anyone knows how to test these before I go through all the trouble of tearing everything down and putting it back together again.

 

[jasonjc]

My thinking is the 14451 cups on the new piston should work. The 14451 cups on the old two piece piston get expanded too much , in my opinion. I was also thinking about getting some other cylinders (for the pistons) or just pistons to put in my cylinders that use the cup type cups instead of the ring type cups.

 

[USMC 00-08]

I was also thinking about getting some other cylinders (for the pistons) or just pistons to put in my cylinders that use the cup type cups instead of the ring type cups.

I like that idea.

For now, I am going to try the 14451 cups on the new pistons. I'm going to block off the rear brakes for now and just test this on the front to see how it holds up before I do the remaining 8.

 

[Another Ahab]

I like that idea.

For now, I am going to try the 14451 cups on the new pistons. I'm going to block off the rear brakes for now and just test this on the front to see how it holds up before I do the remaining 8.

That's smart thinking. I can recall the times (embarrassingly more than once), when I undertook a fix of something and kept moving because of the momentum, only to discover just as i finished up that I had done it all wrong. Doh! And start over.

 

[USMC 00-08]

As of today, the front brakes are redone. The wheel cylinders were lightly honed just in case there were any burrs and new Napa cups put on the one piece pistons. The back brakes are blocked off and air is bled out of the system. Now we watch to see if any leaks happen. As soon as I get the truck to run correctly, I will road test.

While going through the new wheel cylinders, I did not see anything that would cause them to leak.

I did check the master cylinder vent as suggested and it was clear.

 

[hambone]

Here is the pic of my new wheel cyls. you requested. Hambone

 

[USMC 00-08]

Thank you. That piston looks different from mine. Is it one piece?

Got the truck running very good and plan to road test this weekend. So far no leaks with the NAPA cups. I'll report back after I get it on the road and work the brakes a bit.

 

[Another Ahab]

Thank you. That piston looks different from mine. Is it one piece?

Got the truck running very good and plan to road test this weekend. So far no leaks with the NAPA cups. I'll report back after I get it on the road and work the brakes a bit.

I sure hope it all works for you USMC, because you've really been going through it here with this wheel cylinder issue.

 

[hambone]

It is a one piece piston

 

[USMC 00-08]

So far, no leaks yet. Will keep watching.

 

[USMC 00-08]

As of last weekend, still no leaks. I decided to put a new master cylinder on and rebuild the airpak. We'll see how the wheels cylinders hold up after all that is done.

 

[USMC 00-08]

The new master cylinder and rebuilt airpak have been installed since Christmas day. No leaks and the truck is stopping great. I'll be doing the same thing to the rear wheel cylinders soon and will hook the back brakes up again.

 

[Another Ahab]

The new master cylinder and rebuilt airpak have been installed since Christmas day. No leaks and the truck is stopping great. I'll be doing the same thing to the rear wheel cylinders soon and will hook the back brakes up again.[/QUOTE]

Am I reading that wrong:

You've been stopping with brakes on your front axle only!?

 

[USMC 00-08]

You read it right. I did not want to redo all 12 of the brand new wheel cylinders to find out they all still leak like they did when I installed them. It is a large amount of work to keep doing over and over, so I decided to redo the fronts with new seals to see if they held up while testing them with the new master cylinder and rebuilt airpak.

I will now pull off all four rear wheels and rebuild the remaining 8 wheel cylinders. You would not believe how well this truck stops with a functioning airpak and only front brakes. I believe people who say these trucks will stop on a dime with all 6 wheels having functional brakes.

 

[SturmTyger380]

Yes. Wheel lock up is very easy with the stock brake setup. If you are off road you can always count on it if you jab the brakes.

 

[USMC 00-08]

Here we go again. I rebuilt all of the new rear wheel cylinders in July, complete with new seals, honed them, etc. After everything was hooked back up, installed and brakes adjusted, everything worked perfectly when tested on jack stands. Yesterday I noticed I have a leaker again. A little over 2.5 months since they were rebuilt. I probably have not started the truck since July.

Does the truck just sitting with no use cause this? I am at a loss. The truck is sitting on jack stands as I continue work on it. I am getting close to setting her down where I can move her again and saw the leak.

 

[Another Ahab]

Here we go again. I rebuilt all of the new rear wheel cylinders in July, complete with new seals, honed them, etc. After everything was hooked back up, installed and brakes adjusted, everything worked perfectly when tested on jack stands. Yesterday I noticed I have a leaker again. A little over 2.5 months since they were rebuilt. I probably have not started the truck since July.

That's a drag. You do everything right, by the book; and you STILL get a kick in the pants.

It's the Book of Job. Do you know your King James?!

 

[USMC 00-08]

I sure do. I suppose Job had it far worse, but this is still so frustrating. I might block the brake line off to the offending wheel. 5 wheels stopping might have to do for a while.

I hope some of the guys that used these extensively in the Canadian service will chime in with some solutions or anyone that has had this problem and found how to keep it from happening.

 

[USMC 00-08]

It has been almost a year and I am still dealing with wheel cylinders leaking one by one. I've decided to get the Wagner WC15306 cylinders or give Ralph at Niagara a call to see if he still has NOS Canadian surplus wheel cylinders.

Hopefully those will be the solution. I've gotten quite good at pulling the hubs, packing bearings, replacing seals, etc., but I'm sure tired of it.

 

[DUUANE]

There is a service in ontario that will machine your cylinders and press in a brass sleve. Use silicone brake fluid , lube up all your seals with sil-glide or equivalent silicone rubber grease prior assembly and never worry again. Oh and a touch of copper anti sieze on the EXTERNAL threads of your bleeder screws.