If you have an M105A2 with an undamaged valve ...

[KaiserM109]

Emergency Relay Valve problems

I have a 1986 M105A2 and a 1990 M105A2 trailer. The Emergency Relay Valve does not look anything like the unit depicted in TM9-23300-213-14&P. There seems to be a part missing on each and another broken on the ’86.

I saw a broken part on the ’86 and went to look at the ’90 to see what it looked like. When I touched the bottom of it, a rubber gasket about 1 ¼ inch across and a thin steel washer about 5/8 inch across fell off. There is a plastic part sticking down that has a ridge in it like there used to be a keeper. When I put the gasket and washer back on, there was nothing to hold them, so they fell off again. They must have been stuck there from dried something or other.

I went back to the ’86 and could see that it was the same, except the plastic part sticking down was broken off. I have not hooked the trailers up to test the brakes yet, so I do not have any idea if they work. Does anyone have any idea what parts I am missing?

 

[doghead]

RE: Emergency Relay Valve problems

That is the dust flap thingie(kinda like a check-valve). It will still work with out it(for awhile).

 

[Recovry4x4]

RE: Emergency Relay Valve problems

While we're on the subject of relay valves, I could use one if anyone is boning out another M105 type trailer.

 

[KaiserM109]

RE: Emergency Relay Valve problems

That is the dust flap thingie(kinda like a check-valve). It will still work with out it(for awhile).

I guess I could cover it with DUCT TAPE!! Can I get replacements? Is there any sort of equivelent in the civilian world?

While we're on the subject of M105 brakes how in the #$%# do they work? We were all prepared to release the brakes to haul them away, but they roled fine (after I threw gravel and then released the parking brakes).

I have messed around the back of the deuce with it running with the parking brake set and saw that there was pressure on the lines. My guess, and please correct or confirm this, when everything is hooked up and the tank on the trailer is pressurized, pressure on the lines from the deuce releases the brakes and the lack of pressure sets them. This weekend I will bring the deuce around and hook it up. It isn't legal for the road yet, so I either sneak around or limit myself to the parking lot.

My deuce in storage makes me feel like the week before Christmas!

 

[Recovry4x4]

RE: Emergency Relay Valve problems

There are 2 different braking systems. Those with the relay valve and those without. Those without are very simple. If the air line (only one) is hooked up to the service side of the deuce and the valve is open then it works like this. As you apply brakes on the truck, the air pack meters a proportionate amount of air back to the trailer. The chamber applies the master cylinder and the trailer brakes. The problem with this system is no breakaway brakes. With the relay valve you have 2 air lines. Once with service air and one with emergency air. The emrgency air fills up the air tank on the trailer and puts the brakes in standby. Again when you apply the brakes, the metered air is sent to the trailer but this time it is sent to the relay valve. It relays the signal to the air supply on the trailer and releases the same metered amount of air to the chamber to apply the brakes. If for some reason you lose the air pressure in the emergency line, the relay valve sends and "Oh Sh!t" message to the chamber and the wheels of the trailer cease to turn. You will also find that if you are travelling and decide to stop for the night, as the air bleeds down the relay valve freaks out and sends the same "Oh Sh!t" message to the brakes and you can't take off. You simply crawl under the trailer and release all the air from the reservoir and start anew. Just remember to shut off the valve on the emergency line and make sure the trucks brakes are set before releasing the trailer brakes.

Oh, BTW don't cover that port, it's the exhaust port for releasing the brakes.

 

[KaiserM109]

RE: Emergency Relay Valve problems

Kenny,
Thanks for the info. I went to the TM and looked at which hose was which and remember that the glad hand I opened up was the right (emergency) one, which explains why it had pressure with the brakes off. I didn’t mess with the other one.

I HAVE A LOT TO LEARN!!

Oh, BTW don't cover that port, it's the exhaust port for releasing the brakes.

Don't I need to cover it somehow to keep the insides clean? I can see some stuff up in there that doesn't look like it will tolerate dust and dirt very well.

Can anyone tell/show me what it looks like complete? Possibly I could fab’ a replacement. I’m about to sell one of these trailers as “complete” and I don’t want to just pass off the problem.

 

[Recovry4x4]

RE: Emergency Relay Valve problems

If you tape it, you may prohibit it from releasing all the way. You could put in a piece of oil bath air cleaner foam but you will have to tie it in so that when it starts to clog, it's not simply blown away.

 

[devilman96]

RE: Emergency Relay Valve problems

Kenny I believe I have those valves. Any chance you can bring the trailer over AGAIN? lol

 

[Recovry4x4]

RE: Emergency Relay Valve problems

Eventually I can. I've not moved it since it came home. Might be able to save this one

 

[vinny-socom1]

RE: Emergency Relay Valve problems

Kenny,

I've got some M105 trailer parts let me know what you need.. Vinny

 

[Jones]

RE: Emergency Relay Valve problems

The exhaust Kenny is refering to has to be allowed to vent or the brakes won't release. The rubber on the end of the vent helps keep out dust but more importantly, it keeps out nesting insects. It's called a 'wasp excluder' for a very good reason.

 

[KaiserM109]

RE: Emergency Relay Valve problems

What did the thing look like? Where can I get a replacement?

I will tape something over it for now just to keep bugs out, but I need to know what to tell the buyer. I don't feel like just sliding it by him, although it would be easy to do.

This looks like a fragile part, something quite apart from the rest of the M105's nature. It's just about the lowest point on the trailer and seems to be suseptable to high-centering damage. The rest of the '86 trailer seems to have been handled well while the '90 shows damage on the back top from being strapped down with chains and on the front wall from a forklift. I'm guessing a forklift did this damage too.

This trailer has HUGE lifting and tie-down points. Maybe they should be built with forklift guides too!

 

[KaiserM109]

RE: Emergency Relay Valve problems

It's called a 'wasp excluder' for a very good reason.

<- SUPER VALUABLE PIECE OF INFO.

I Googled "wasp excluder" and got all kinds of bulletins, etc. I am going back to the storage lot and look at the valve to see who manufactured it. I’ll bet there’s a source on parts and maybe whole assemblies.

 

[jasonjc]

RE: Emergency Relay Valve problems

I too think forklift guides are in order. All 3 of my newer 105's all have the vale broken in some way.

 

[KaiserM109]

RE: Emergency Relay Valve problems

Jason,
I saw an earlier post by you where you brought home some newer 105s and I was about to PM you to see if you had had the same experience. I guess you can't give me a picture of an undamaged valve, then.

Edit:

Looking at the photo that I posted above, the thought occured to me 'Is it possible that this valve is installed up-side-down?'

Would the valve work if it was turned over and the vulnerable part facing the bed?

 

[devilman96]

RE: Emergency Relay Valve problems

Guys im getting one of these from Vinny so I can get them into the store... Might take a few weeks but I will post them when their in.

 

[Jones]

Here are some pictures of the relay valves on the baby HEMTT so you can see what the vents look like. Almost all of the brake parts are Bendix and I've got a friend checking on the vents but he thinks they're only available as part of a rebuilt kit and not serviced seperately. The other vent is made by New York Air Brake and I've screwed one in each of my quick release valves to protect them too.

 

[KaiserM109]

A little more info: The valves have Midland canst into the top, but I cannot find any part numbers.

Here are a couple of pic's

 

[Jones]

My air brake shop IDed it and says they have some core relay valves that can be parted out. I think there's a Bendix replacement if you want to switch brands. Sounds like they all mount the same and do the same job.

 

[KaiserM109]

What would be nice is to be able to get just the broken wasp excluder replaced. I priced the complete valves and found that they run from $100 to $150, a high price to pay for a couple of bucks of plastic and rubber.

I emailed Midland about this, but I don't expect a reply for a few days.

I would be interested in knowing how wide spread this problem is. If somebody reading this has an M105A2 would you please check this part and let me know if you have a problem. Take a look at the 2nd picture. There is something missing that apparently attaches to that stem in the middle. If you have a complete one, please photo it and send us a pic'.

You can PM me or post it here.