M105A2 Brake Inspection

[Wildchild467]

I think i have a brake dragging some on my M105A2. I dont have the 3-3/8" or 3-7/16" socket to pull the hub off to get to the brakes. is it possible to take off the 3/8" nuts that hold the drum on to access the brakes? I tried adjusting them, checked parking brakes incase they were tight, released the air and still the left side wheel does not spin as freely as it should. I looked at the TM's and it appears i can just remove the drum where on the M105A1 it looks like i may not be able to because of the grease shield. I am going to the rausch creek rally this evening and it would be comforting to know i wont have a brake dragging. another thing i could have tried is to leave the brake adjustment loose and drive the truck and trailer to work this morning and see if the excersize frees it up.... but if there is a problem, id rather fix it properly.

so after all that rambling, can i just pull the drum off to check the brakes? if not, what size socket is it....3-3/8" or 3-7/16'?

 

[WillWagner]

You can take the drum off and leave the hub on. If the shoes are tight, you'll have a hard time getting the drum off.

 

[Wildchild467]

Here is a picture i copied from the TM. I just thought i would post this to help show anybody else what i was looking at. I know on my deuce, i cant just pull the drum off by itself, but in the M105A2, i can. As you can see, the bolts that hold the drum on (18 of them i think) are not bolts, but look like actual press in studs. I am going to pull the drum off and see what it looks like in there.... hope the drum isnt rusted on there too bad!

 

[SFGABN@5th]

Well look learn somthing every day.

Kevin

 

[shenkmen]

I'm liking this thread since I just picked up a 2006 M105A2.

Are the brake shoes on the M105A2 the same as a M35A2? I cross referenced the NSN's and they do not match. I've read other threads which state they are and are not the same.

Do some match and not others do not?

Thanks

 

[rosco]

IF you can get the drum off, I doubt that it will help much. Its been a long time since I had mine apart, but I think that you have to take the hub off. Lots of folks don't have the proper socket - use a chisel/punch/screwdriver to take the nut off and on. Often stuff gets dirty in there, causing things to drag. Also, a broken spring will cause it to drag. Take the hub off!.

 

[Wildchild467]

My dad is retired, so he is actually working on my trailer for me now because my time is limited after i get out of work. thats mighty nice of him isnt it?? I talked to him just a little bit ago and he was saying the drum could come off but was still hard to see in there. he said the brake shoes look darn near brand new and everything appeared to look ok, so maybe they just need some excersize.

Shenkmen,

The M105A1 has different brakes than the M105A2. the M105A2 has brakes very similiar to the deuce. as far as part numbers, i am not sure. who knows though, maybe the linings are the same and could be swapped... but dont quote me on that one. The M105A1 has one wheel cylinder per side (2 total) and the M105A2 has 2 wheel cylinders per side (4 total). They both work, but maybe the brake performance for the M105A2 brakes is a little better? Not sure. Both have worked and been in service a long time and have been proven designs.

 

[Wildchild467]

oh, to rosco's comment, i agree, ill have to pull them off someday and give everything a good look through.

 

[emmado22]

Have you checked your relay valve and MC? Make sure relay valve is operating correctly, and MC is filled with DOT 5.

 

[Wildchild467]

agreed. I had the relay valve off and sprayed WD-40 in the ports just as a PM. i checked the fluid in the master cylinder and it is full... even though i poured a very little bit of fresh DOT 5 in there. The fluid looked red to me and the Napa DOT 5 i have is purple... anybody know anything about red brake fluid? i know there has to be a thread about brake fluid i could read too. my thinking is that the left side was the one hanging up a little, and the right side seemed to work fine. im sure this trip down to rausch creek will do it good though too. obviously if there is a problem it needs to be fixed, but there is also something to be said about just taking a unit out and using it. to get the rust off things.

 

[porkysplace]

This a good thread on determining what brake fluid you have; Brake fluid -how to tell which kind you have DOT 3

It's good to see you tittled this thread so it will make searching easy.
If more people use tittles like this there would not be near as many complaints about searching the site.

 

[rlwm211]

Did you try adjusting the brake shoes so they are not touching the drums?

Seems to me if you can adjust the brakes to a proper setting your dragging problem may very well go away.

Just my two cents.

RL

 

[mistaken1]

Are the brakes dragging or is it the bearing too tight?

With the drum off can you put the wheel/tire back on to see how it spins?

 

[Robert Long]

What do you guys run on service intervals on these at all? If I'm not using the brake setup other than the manual parking brakes, is there anything to be watchful of?

 

[Wildchild467]

I really have not used my trailer enough to warrant a brake inspection from regular usage. I just want to inspect the brakes to make sure everything is the way it should be so everything is working properly. Who knows how long my trailer sat before I got it and want to make sur everything works good and is well PMed.

I have not seen many pictures on the site about working on M105A2 brakes. Even pictures were hard to find it seemed. Last weekend I took my wheel cylinders apart on the trailer to see why one brake always wants to drag. The cylinder looked brand new, but I think it just needed to be exercised. The brake works better now but really likes to lock up more than the other side. My plan is to loosen the brakes adjustment on the backing plate so the pistons in the wheel cylinders have to travel farther to work. I think that will help free things up also. Another idea I had was maybe there is a way I can modify the relay valve some so that there is less brake pressure going to the wheels. I am not sure if that is possible or not by adjusting the spring pressure (with shims) inside the relay valve. There is another thread about relay valves which I am going to discuss that.

Another thing I would not recommend (somebody is free to chime in if they have another point of view) is not to use the parking brake for an extended period of time (months on end). The brake shoes pressed against the drum may cause them to rust the shoes to the drum and make the drum have a pulsing action when using the brakes. This would not last long as it should clean itself up quick. The other reason is maybe the wheel cylinders get stuck in that one position and have a hard time to free themselves up. Obviously block the wheels when the trailer is not in use. As you can see in the 2 pictures, the push rods to the brake shoes are at an angle, because the pistons are not retracting in the cylinders. i believe that was causing my brakes to drag.