m1083 weak brakes

[SamWillis]

Hi All, I'm a first-time poster. I bought a GovPlanet Hawaii m1083A1 (my first FMTV!) and I just received my EUC. So I'll do a hop to Honolulu and pick up the truck and prepare for RoRo shipping to Oakland. Btw, thanks to Fuzzy. He's already provided me with very helpful info on my Hawaii logistics.

The rig is a runner, but the brake inspection report said both the service and parking brakes are weak. I'm hoping I can fix the brakes myself...so, I've been doing a lot of research on YouTube and here on SS.

I've watched and read a lot of information to understand the basics of how brakes work on these rigs. I've watched Endless Adventures YouTube video on FMTV Brake Service and several others on the Threadle Valve are system all the way to the Brakes. I'm trying to figure out what might cause weak parking and service brakes, but the most brake posts address brakes locking up. So I'm stuck. I also hired Adept Ape (Josh) to review the GovPlanet photos and videos with me to check out the engine prior to purchase and he said the brakes could be a simple adjustment, but we didn't have time to get further into that.

So, any suggestions on how to troubleshoot this or what might lead to weak service brakes would be greatly appreciated.

I have also downloaded all the TMs, but have struggled to make sense, I have not yet found the troubleshooting section, but I will continue to read and try to find this section and the possible issues.

Thanks for any help or guidance anyone can provide. And I'm looking forward to my new FMTV adventure!

 

[NDT]

Sounds like multiple wedge brakes are stuck retracted due to corrosion.

 

[GeneralDisorder]

Everything in the Hawaiian Army units rusts so badly it's almost sure to be corrosion related. Only place I've ever trained where we were replacing entire brake line kits on HMMWV's. Literally entire rubbermaid trash cans full of rotted out hydraulic brake lines. Had a hard top cab on a 5 ton break loose at the back wall and fold forward onto the hood during a hard stop. Needless to say they preferred canvas tops and soft door HMMWV's (doors typically removed in garrison). Worst corrosion I've ever seen on military hardware on those islands. Also the Hawaiian National Guard were some of the most ate-up from the neck-up, rag-tag group of joe's I've ever encountered. The WALL of beer cans lining the side of the motorpool, and the belts of live ammo sitting rusting on pallets was a sight to behold. They did have AMAZING BBQ skills though. Darn good burgers.

How are you planning to register that in the People's Socialist Republic of California?

 

[Ronmar]

Wedge brakes have a very small travel so proper adjust is important. The spring and service both being weak is an exent clue that points to misadjustment or damaged hardware. With the brakes released you should only have I think .020" between shoe and drum faces at the mide of the shoe(its in the manual, use a feeler gauge to check).

If the auto adjusters are gummed up or damaged, shoe wear woukd steadilly increase this gap untill the wedge cannot close it.

Mine pulled to the right, what I found were shoes installed backwards(they are stamped as to which end goes toward the adjuster/actuator). This damaged the adjuster star wheels which disabled the auto adjusters. As the gap got larger and larger, the wedge extended further and further untill it reached its limit. The wedge sets between two rollers in a captive frame/cage assy. Over-extending it popped the cage apart disabeling the wedge mechanism.

On the other side only one shoe was installed backwards, so only one shoe was out of wack, and the total gap had not grown large enough to over-extend and damage the wedge assy.

I posted about it here with some pics, once upon a few years ago...

 

[SamWillis]

Everything in the Hawaiian Army units rusts so badly it's almost sure to be corrosion related. Only place I've ever trained where we were replacing entire brake line kits on HMMWV's. Literally entire rubbermaid trash cans full of rotted out hydraulic brake lines. Had a hard top cab on a 5 ton break loose at the back wall and fold forward onto the hood during a hard stop. Needless to say they preferred canvas tops and soft door HMMWV's (doors typically removed in garrison). Worst corrosion I've ever seen on military hardware on those islands. Also the Hawaiian National Guard were some of the most ate-up from the neck-up, rag-tag group of joe's I've ever encountered. The WALL of beer cans lining the side of the motorpool, and the belts of live ammo sitting rusting on pallets was a sight to behold. They did have AMAZING BBQ skills though. Darn good burgers.

How are you planning to register that in the People's Socialist Republic of California?

Getting it registered with a title in Montana through govplanet. Then it will have a legit VIN and title. So once I get it converted to an RV, then I'll register it in California as an RV. My fingers are crossed that this plan works.

 

[serpico760]

Getting it registered with a title in Montana through govplanet. Then it will have a legit VIN and title. So once I get it converted to an RV, then I'll register it in California as an RV. My fingers are crossed that this plan works.

Sounds like a very familiar plan!
What are you planning to do for the habitat? If you can afford it go with RVglobetrekker.com. You can watch Dave Anderson's videos on those on YouTube.

 

[chucky]

???? If the shoes are worn down some could it just need all the brakes adjusted back up tight so you have more braking ability ?

 

[Third From Texas]

Read up on how dangerous those brake cans can be.

And be damned careful with 'em if you need to get into one.

 

[SamWillis]

Sounds like a very familiar plan!
What are you planning to do for the habitat? If you can afford it go with RVglobetrekker.com. You can watch Dave Anderson's videos on those on YouTube.

I've watched the RVGlobeTrekker video series numerous times. And many of Dave's (Helicool) FMTV videos. Great stuff. Unfortunately, that RV Globe Trekker setup is too costly for me—especially habitat for the m1083. My brother-in-law is teaching this old dog how to weld aluminum so I'll be building my own habitat from scratch. A journey I'm really looking forward to.

 

[SamWillis]

Sounds like a very familiar plan!
What are you planning to do for the habitat? If you can afford it go with RVglobetrekker.com. You can watch Dave Anderson's videos on those on YouTube.

Did you do the Montana title, get a clean registration/title, and then register it in California? Or another state? Did it work? Any pitfalls I should be aware of?

 

[SamWillis]

Ok, good feedback. Sounds like my number one issue to look for is corrosion and locked-up brake parts. The second is to look for faulty parts or parts that were incorrectly installed. And third is to possibly do some fine brake adjustments.

Additionally, I'll continue my attempts to decipher the TMs.

Thank you very much for the help. Now I'll rewatch Endless Adventure's "FMTV Brake Service" YouTube video another 4 or 5 times.

 

[serpico760]

Did you do the Montana title, get a clean registration/title, and then register it in California? Or another state? Did it work? Any pitfalls I should be aware of?

I bought my truck from d&b equipment in Lena Wisconsin. They had already done all the paperwork with the auction and the government and it already had a Wisconsin title. And like you once it's finally an RV i'll figure out the next step. My habitat is an m313 expansible van trailer that I will take the box from. It's still bare bones and still mounted to the trailer frame so my truck still looks like a standard M1083 but with an actual nice interior now! For more inspiration on your build you could check out adventure athlete and Nate Volk. They have both made some nice habitats from scratch like you intend to. And even if you don't get globetrokrackers habitat I do suggest you integrate their zero torsion mounts. I have found on McMaster-Carr what I believe is the bearing that they are using and also the keeper. I can post a part numbers of those if you're interested. I'm still debating whether or not to try and integrate their zero torsion mounts or fab something similar up or just do the spring and shackle mounts like these military boxes typically have when they came to the military and like Nate Volk is using. My box is a bit heavier than an aluminum one you would make due to the expansible sides with a heavy duty steel structure and aluminum skin, so it weighs about 6,000 lb before I've put any cabinetry or anything in it.

 

[SamWillis]

Wedge brakes have a very small travel so proper adjust is important. The spring and service both being weak is an exent clue that points to misadjustment or damaged hardware. With the brakes released you should only have I think .020" between shoe and drum faces at the mide of the shoe(its in the manual, use a feeler gauge to check).

If the auto adjusters are gummed up or damaged, shoe wear woukd steadilly increase this gap untill the wedge cannot close it.

Mine pulled to the right, what I found were shoes installed backwards(they are stamped as to which end goes toward the adjuster/actuator). This damaged the adjuster star wheels which disabled the auto adjusters. As the gap got larger and larger, the wedge extended further and further untill it reached its limit. The wedge sets between two rollers in a captive frame/cage assy. Over-extending it popped the cage apart disabeling the wedge mechanism.

On the other side only one shoe was installed backwards, so only one shoe was out of wack, and the total gap had not grown large enough to over-extend and damage the wedge assy.

I posted about it here with some pics, once upon a few years ago...

Ronmar, These are very helpful points and I will look for these issues as I dive into the brakes.

I bought my truck from d&b equipment in Lena Wisconsin. They had already done all the paperwork with the auction and the government and it already had a Wisconsin title. And like you once it's finally an RV i'll figure out the next step. My habitat is an m313 expansible van trailer that I will take the box from. It's still bare bones and still mounted to the trailer frame so my truck still looks like a standard M1083 but with an actual nice interior now! For more inspiration on your build you could check out adventure athlete and Nate Volk. They have both made some nice habitats from scratch like you intend to. And even if you don't get globetrokrackers habitat I do suggest you integrate their zero torsion mounts. I have found on McMaster-Carr what I believe is the bearing that they are using and also the keeper. I can post a part numbers of those if you're interested. I'm still debating whether or not to try and integrate their zero torsion mounts or fab something similar up or just do the spring and shackle mounts like these military boxes typically have when they came to the military and like Nate Volk is using. My box is a bit heavier than an aluminum one you would make due to the expansible sides with a heavy duty steel structure and aluminum skin, so it weighs about 6,000 lb before I've put any cabinetry or anything in it.

Ohhhhh..., Great info. That's exactly what I was hoping to do. Integrate a similar sub torsion mount system. So, yes, post numbers would be greatly appreciated!

I will definitely check out Adventure Athlete and Nate Volk. It's great to find inspiration from those who have done good work with clever ideas.

I feel compelled to do the zero torsion mounts over spring and shackle due to weight, but honestly, I haven't investigated this enough at this point. So I really appreciate you sharing the knowledge.

 

[serpico760]

Ronmar, These are very helpful points and I will look for these issues as I dive into the brakes.

Ohhhhh..., Great info. That's exactly what I was hoping to do. Integrate a similar sub torsion mount system. So, yes, post numbers would be greatly appreciated!

I will definitely check out Adventure Athlete and Nate Volk. It's great to find inspiration from those who have done good work with clever ideas.

I feel compelled to do the zero torsion mounts over spring and shackle due to weight, but honestly, I haven't investigated this enough at this point. So I really appreciate you sharing the knowledge.

If you do fab up your own mounts, I suggest you make them out of all the same thickness steel and find a good water jet place near you. My experience from using water jet for industrial machine components is it has a very nice surface finish and if you just need a bunch of parts out of one sheet the cost is pretty low. For example the shop near me would charge I think about $200 to cut a whole bunch of parts out of one sheet. One nice trick I tend to utilize when I can is if I have to cut a big chunk out of one part for weight savings I try to design that area such as the piece that cuts out of it I used for something else. For example if you cut triangles out of a piece for weight savings while maintaining the strength, you can design those triangles such that they're gussets that you'll use in other places. Just be sure to tell the water jet shop that you want all the pieces back even what they think is the throw out cut away pieces. Just realize that triangles and other features that are too small may fall between the slats in the water jet table and be unretrievable. Utilize tabs and slots in your design that make for easy assembly. Keep in mind all the edges will have a slight angle to them unless the shop has a multiaxis water jet machine that can cut in an angle to counteract the kerf.