Other than it being really cold the last two months I have had a number of things going on but I kept working on the underside of the cab. I spent hours scraping and using a wire brush in an air tool to clean the underside of the cab and the frame. I am tired of working under the cab. But I think all the rust is gone and it's in a lot better shape. I will keep working my way backwards on the frame and then eventually to the front as well.
Years ago I drove a M37 that had power brakes and the older guy had installed a Hydrovac under the cab. So I found one and have started restoring it to use. It's in fairly good shape. I found a rebuild kit for it as well. When I get done I will share more pictures of the process.
Hi Alan,
Looks like that’s a Bendix booster- any idea what the original application was?
Also, who carries rebuild kits for them and are they nos or new? I’ve heard some people having problems with nos booster kits, I guess because the diaphragms don’t always age well. Supposedly the xm708 had a booster, but I’ve never checked them out in detail but it might make sense to do it the same way (?)
Best regards, Doug
Made up 500 rounds of 9 mm yesterday, another 500 to make up today. Have a competition IDPA shoot tomorrow. Just something so peaceful, being out my garage, at my reloading bench, seeing so many shiny brass projectiles fall into the small plastic box. Off to test them in a few minutes. But in my Heckler & Koch's , of course they work. H&K's always work.
Yeah there is a guy down in Ga that has started producing the kits as new. https://harmonclassicbrakes.com/ They ain't cheap but NOS kits are getting up there too and they are old now.
The web site is a pain. If you can get to where you can browse the catalog you can actually find stuff.
I am not sure of the vehicle it came off of. I actually got two used units to help me have enough good parts to rebuild. The first unit has smaller brass fittings than the M37 uses. The second one has the 7/16 size brass fittings. Neither units have a check valve which is good as the M37 master cylinder has the check valve in it. When I got into the atmospheric valve of the one with the 7/16 fittings, I found out it is also has a larger size piston but it is pitted where the brake fluid pressure opens the air valve. I think it needs to match. So I will fire up the milling machine and try to over bore the valve and put a brass sleeve in it.
Today the weather was perfect so I got the M37 out and sand blasted the drivers side rear corner of the frame. That was the area that had the heavy rust on it.
Here is the before after I have scraped the rear frame.
After the sand blasting I took phosphoric acid and treated that part of the frame for rust. I like doing this instead of something like POR. I can see that the rust was killed before I put primer on it.
It was a good weekend to get things done. Here is what the hubs looked like after I pulled the drums off:
So this weekend I pulled the hubs, removed all the brake parts and sand blasted the backing plate. Then I put phosphoric acid on to kill any rust that was left.
sturmtyger380 wrote:It was a good weekend to get things done. Here is what the hubs looked like after I pulled the drums off:
So this weekend I pulled the hubs, removed all the brake parts and sand blasted the backing plate. Then I put phosphoric acid on to kill any rust that was left.
Looking better!
“When a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, IT IS THEIR RIGHT, IT IS THEIR DUTY, TO THROW OFF SUCH GOVERNMENT...” -Declaration of Independence, 1776
I got to leave work a little early to make up for extra hours I spent. Got home and cleaned the bearings on the drivers rear. They were not horrible but there were still scoring lines on the rollers. So I would like to have better bearings if I am redoing the whole truck.
Since I have two junk trucks I decided to pull all four rear hubs with the drum attached. If I could use parts off of these trucks it would help pay for me dragging them home. I am getting good at pulling hubs. I ran out of time to clean and inspect the bearings from these 4 hubs. But one truck had what appeared to be new brake shoe linings. So the drum may have little wear as well. I will check the thickness.
If you start swapping drums is that an issue? Do they need to be turned with the bearings installed to turn true?
sturmtyger380 wrote:I got to leave work a little early to make up for extra hours I spent. Got home and cleaned the bearings on the drivers rear. They were not horrible but there were still scoring lines on the rollers. So I would like to have better bearings if I am redoing the whole truck.
Since I have two junk trucks I decided to pull all four rear hubs with the drum attached. If I could use parts off of these trucks it would help pay for me dragging them home. I am getting good at pulling hubs. I ran out of time to clean and inspect the bearings from these 4 hubs. But one truck had what appeared to be new brake shoe linings. So the drum may have little wear as well. I will check the thickness.
If you start swapping drums is that an issue? Do they need to be turned with the bearings installed to turn true?
I have always been told that you must replace the bearings and races as a set, as they wear together- using a worn part with a new part will accelerate wear on the new part.
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