Brake problem??

[Brad]

We have finally got this 1952 M135 running pretty decent.
Now we can concentrate on all the smaller things.
One thing I just experienced though that is no small matter is a brake problem.
Occasionall when applying the brakes it feels like the brake pedal is against something that will not let it depress.
It is like pushing against a wall. The pedal will not depress and there ate no brakes.
I looked all over and under and the linkage, etc is not hitting a thing?
Any ideas?
Regards and thanks,
Brad

 

[NDT]

Air-pac not actuating?

 

[YkDave]

could be a couple of things...

If the pedal gets rock hard like its hitting something, its possible that their is junk in the master cylinder and its jamming up the piston.

If the pedal gets really stiff but not 'solid' its likely an airpac problem (essentially no power brakes, just like jumping into a modern vehicle and trying to hit the brakes when the engine is off and their is no vacuum reserve left)

 

[Oldfart]

Could your line lock be On??? (The electric emergency brake.) Having just rebuilt an air pak, I would say all sorts of problems could be come and go issues with a faulty air pak. We discovered a spring that rusted in two on our rebuild. This spring was a counter balance spring on the air side of a piston and I am sure caused eratic operation of our air pak. That coupled with some worn out seals only compounded our symptoms.

 

[Brad]

Problem continues, actually getting more frequent....
I rebuilt the master cylinder, which looked fine inside. I also totally removed the electric temporary emergency brakee.
Bled the brakes and got good pedal. Took a ride and have the same problem.
I noticed that while braking and working normally, all of a sudden the pedal got hard while pushing.
Usually when I release and pump a few times thet will work.
Seems best if I rev engine and double clutch.
Oh, did I memtion we changed this over to a standard shift? We fought the auto tranny for two years.
Sure need to get these brakes working. I think I am going to remove and tear down the Air Hydo Cylinder. I dont know what else it could be. MAybe I'll find something obvious in there.
One thing, when we changed the tranny over we plugged allot of lines. If I plugged the Air Vent line on the cylinder, could that cause a problem??
Thanks all for the help,
Brad Foust
Keep Yer Powder Dry, (your gonna need it)

 

[Oldfart]

http://www.steelsoldiers.com/early-deuce/70703-m220-airpak-rebuild.html

 

[Brad]

OK, here's another idea. A local mechanic friend of mune says this will not work. My Dad, who drove the older WWII trucks in Korea says this will work.
He says to simply By-Pass the air pack and go basic hydraulic brakes.
What do yo guys thinKK??
Thanks

 

[jasonjc]

No air pac NO power brakes. I hope you have strong legs.

 

[Brad]

What is that supposed to mean?? Really, I just come on here asking advise from folks that seem to be pretty well intentioned.
If I bothered you, I apologize. But the man with the opinion you ridiculed is the same man that drove one of these WWII trucks at the Josin Resivour in Korea, if you might be familiar with the history of the 7th Division there, of which he was a part.
Again, my apologies, I wont bother you any more.
Brad Foust

 

[USMC 00-08]

Calm down brother. I don't think anyone is ridiculing anybody. I think I see where you would take offense, but that is his signature line and not directed at your father. I am sure no one here would have anything but respect for anyone that served at the Chosin Reservoir.

You are not bothering anyone and asked an intelligent question. Maybe it will work and maybe it won't. Let us know what you figure out. I would be interested in the results.

 

[Flyingvan911]

What jasonjc is saying is that without air pressure from the airpac, the brake system is manual. You will have to put a lot of force on brake pedal to get the truck stopped in a reasonable distance. An emergency stop will be almost impossible. It will be much safer if you have a working airpac.

 

[Brad]

the only thing we have extra pertaining to BED parts is all the wood bows, and maybe some tarps.
I see where I may have mis-read Jason's comments. And I guess I did,.
Sorry about that. I should have thought a little more before reacting.
My Da is gonna be 82 soon and not getting any better. So I am really frustrated in getting this truck road worthy.
I by passed the air pac, but they are just too hard to push, as was advised.
Si now I guess I'll try and make an air pac out of the two we have.
But I am not a mechanic and dont know whats wrong with this thing.
It looks perfect inside, clean, etc.
One thing though I think was wrong is that it had brake fluid on the back side of the air pac cylinder.
Again, please excuse my quick reaction.

Brad

 

[Oldfart]

the only thing we have extra pertaining to BED parts is all the wood bows, and maybe some tarps.
I see where I may have mis-read Jason's comments. And I guess I did,.
Sorry about that. I should have thought a little more before reacting.
My Da is gonna be 82 soon and not getting any better. So I am really frustrated in getting this truck road worthy.
I by passed the air pac, but they are just too hard to push, as was advised.
Si now I guess I'll try and make an air pac out of the two we have.
But I am not a mechanic and dont know whats wrong with this thing.
It looks perfect inside, clean, etc.
One thing though I think was wrong is that it had brake fluid on the back side of the air pac cylinder.
Again, please excuse my quick reaction.

Brad

The 5 ton air pack rebuild kit has all the seals necessary to rebuild the M211/M135 Air-Pak EXCEPT for two small cups. We could not find any M211 series rebuild kits even aver a couple months of searching. The 5 Ton kits are available on eBay and we got ours for less than $50.

 

[Brad]

Well we might have gotten lucky with this.
I found the cup in the hyd cyd in the air pac might worn and luckily had one from the other to replace it with, Also switched the air pac big piston.
Cleaned it all up and tried it,
SO FAR SO GOOD! Working perfectly.
Thanks for all the advice and help.
Brad

 

[S*M*A*S*H]

Calm down brother. I don't think anyone is ridiculing anybody. I think I see where you would take offense, but that is his signature line and not directed at your father. I am sure no one here would have anything but respect for anyone that served at the Chosin Reservoir.

You are not bothering anyone and asked an intelligent question. Maybe it will work and maybe it won't. Let us know what you figure out. I would be interested in the results.

i would like to know if that works i just bought a m135 and am trying to get it running but some body cut all the air lines out of the vehicle and i not sure wat to do with it but if the hydraulic brakes will work manualy thats would be good for me

 

[S*M*A*S*H]

is it possible to put in a master cylinder out of a pick up truck or newer 5 ton truck in a m135 and run the stock wheel cyilinders

 

[Oldfart]

I think it will be hard to stop without a brake booster. Depending on the model, they weigh 13,000 to almost 16,000 lbs. empty. If the air pack is still there, then you might consider replacing air lines (if it still has a compressor.)

 

[Brad]

In reply to your question, I know see where I jumped the gun on my response, and that is just his signature reply. As you put it. But I think anyone can see where I took it wrong. For my part, I apologize for any think I might have said to offend. We all need to stick together in this day and age. As we are on the same team.
As for the brake broblem, by-passing the air assist did not work satisfactorily. Whis just slightly better, they are way tooooo hard to use.
We just took everything apart, cleaned it all up, traded some less worn looking rubber cups and now everything works fine.
Leep yer powder dry.
Brad

 

[nattieleather]

The stock brakes on the GMCs are wonderful when they work right. With the air pack working and all the brakes adjusted properly you can stop on a dime and give 8 cents change. Ok maybe more like a quarter and give 20 cents back, but I have owned and worked on both an M211 and a M35A2 and I loved how well the brakes stopped the 211. They are also much easier to adjust and keep adjusted than the M35. If someone could figure out how to make the air pack off the M35 or the 5 ton work on the GMCs you would have something there.

My other thought was to scrap the hydro brake system and install a commercal air brake system, but then do you run into CDL issues?

 

[Oldfart]

The stock brakes on the GMCs are wonderful when they work right. With the air pack working and all the brakes adjusted properly you can stop on a dime and give 8 cents change. Ok maybe more like a quarter and give 20 cents back, but I have owned and worked on both an M211 and a M35A2 and I loved how well the brakes stopped the 211. They are also much easier to adjust and keep adjusted than the M35. If someone could figure out how to make the air pack off the M35 or the 5 ton work on the GMCs you would have something there.

My other thought was to scrap the hydro brake system and install a commercal air brake system, but then do you run into CDL issues?

My son and I figured a way to make the 5 ton Air Pak rebuild kit work to rebuild the M211/M135 series Air Pack. We took the hydraulics power piston out of an old M54 air pack that we had on hand and installed it in our M220 air pack so we were able to replace all the seals using the 5 ton repair kit. The power piston threads in exactly the same on both air packs. Our M220 stops on a dime and we are able to feather the brakes so I don’t put people through the windshield.

http://www.steelsoldiers.com/early-deuce/70703-m220-airpak-rebuild.html