m211 how do I bypass airpac

[Havasurat]

Im stuck here big time. Rebuilt master cylinder replaced wheel cylinders. We know the airpac is bad.. How do I bypass the aipac. I need to be able to move the rig.

 

[doghead]

Explain bypass(do you have an air leak you need to stop, or is it applying the brakes?)

How far must you move it? Does it have to be driven there?

Simply open a bleeder and you'll have no brake pressure and you can move it.

 

[Havasurat]

The truck needs to be moved about 3 miles both up and down some hills.. All 6 wheels are locked up. Replaced the master cylinder first. Then all of the wheel cylinders. brakes still locked up after cpl of times on the pedal. Removed the airpac dissembled for brake fluid in back air cylinder and the rear can is full of corrosion. Also found the pressure releif valve stuck half way back in its travel. So we thought we should just half to put a line from the brake line in to the brake line out. Bleed the system. We get half a peddle travel and the brakes are still locking up all the way around. Did we miss something? Should we take the restrict or out of the Master?

 

[doghead]

Maybe just try it with the air disconnected from your air pack.

It will be extremely difficult to stop without the booster working.

You probably should tow it to where it needs to go.

 

[m1010plowboy]

USMC-008 has a thread about the check valve that IS NOT supposed to be in the G749 MC master cylinder so let's hope that's where pascal is messing with you. If he doesn't chime in I'll knock on his door for clarification.

We have turned the brake adjusters back in the bush to nurse a truck home but deck them on public roads. When you back them off they may rub a little and warm up but you still have brakes. My brakes work well with or without air so those massive brake springs pull the pads away and squeeze the wheel cylinders fairly easy. I have looked at a few pads that weren't assembled correctly and resisted the return springs. If the pads aren't floating properly they can stay planted once a guy pushes the pedal.....but not all at the same time.

This should be easy so we'll follow-up MC info for you.

 

[Havasurat]

USMC-008 has a thread about the check valve that IS NOT supposed to be in the G749 MC master cylinder so let's hope that's where pascal is messing with you. If he doesn't chime in I'll knock on his door for clarification.

We have turned the brake adjusters back in the bush to nurse a truck home but deck them on public roads. When you back them off they may rub a little and warm up but you still have brakes. My brakes work well with or without air so those massive brake springs pull the pads away and squeeze the wheel cylinders fairly easy. I have looked at a few pads that weren't assembled correctly and resisted the return springs. If the pads aren't floating properly they can stay planted once a guy pushes the pedal.....but not all at the same time.

This should be easy so we'll follow-up MC info for you.

We know the pads are off this rig we didn't do that maybe I need to take the drums off and make sure the pads were put on properly. Right now the air pack is completely out of it I'll check the drum issue four pad orientation first and I'll take it from there I will get that done in the a.m. and update the board thank you.

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[m1010plowboy]

Got it, Page 33 has the M35 vs M135 MC - check valve info.

https://www.steelsoldiers.com/showthread.php?125811-1952-M135-W-Winch/page33

He also added another link with pictures so here is the info.

""""""The only difference is the filler pipe, which we would remove from our original and install on the M35 master cylinder, and the residual valve (check valve/salt and pepper shaker top looking thing) which we would remove from the M35 master cylinder. I just confirmed that the intake port and bypass port on my original G749 master cylinder is the same as the M35. There are some pictures on this thread to see what I am talking about.

http://www.steelsoldiers.com/showthr...ld-with-Photos

I am going to order and use a new M35 master cylinder and add and remove the parts previously mentioned. I am convinced it will work! There is nothing else inside that could be different. If you google the function of the residual valve, I am sure that is what caused the problem that Bob Kettler warned us about in his tech tips."""""""

 

[Carboarius]

Make sure that the Mico brake is switched off (temporary parking brake). The Mico switch is an electrically applied check valve that prevents the brake fluid from returning to the master cylinder. I know of a few owners who have completely disabled the Mico switch on their trucks to prevent problems.

 

[Havasurat]

Make sure that the Mico brake is switched off (temporary parking brake). The Mico switch is an electrically applied check valve that prevents the brake fluid from returning to the master cylinder. I know of a few owners who have completely disabled the Mico switch on their trucks to prevent problems.

Mico switch is disconnected.


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[Havasurat]

update.. We found the parking brake electronic valve to be frozen, Once we removed the piston from the valve body the brakes work.. No we just need to find all the parts to rebuild the airpac. Thank you everyone for your suggestions.

 

[m1010plowboy]

Can you show us how you bypass the air/ hydraulic cylinder? Pictures at eleven?

Here is the latest air pack info. https://www.steelsoldiers.com/showthread.php?70703-M220-AirPak-rebuild/page4

 

[Havasurat]

Can you show us how you bypass the air/ hydraulic cylinder? Pictures at eleven?

Here is the latest air pack info. https://www.steelsoldiers.com/showthread.php?70703-M220-AirPak-rebuild/page4

I have left the shop for the weekend I will update on Monday with pictures. And thank you for the link there


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