Got my SEE

[319cssb]

The previous owner said he couldn’t get the brakes to bleed . So that there are no breaks. I noticed that when I run the truck, it doesn’t build over 70 psi in air pressure. There are a bunch of air leaks going on. It’s raining cats and dogs today so I didn’t get to do much but get the truck off of the trailer

 

[eric67camino]

Looks good. Worst case, just drop the bucket, and I bet she'll stop pretty quick. Haha.

 

[glcaines]

Great looking FLU419.
The FLU419 has air over hydraulic brakes. Without adequate air pressure, you can't stop the Unimog, even if going very slow. When I got mine, the crossover air line from the regulator/unloader to the air tank was corroded solid, hence no brakes and a lot of other stuff didn't work. I replaced the 10 mm corroded steel line with a 10 mm 316 stainless steel line and a new unloader I found on Ebay, along with a few fittings I got from EI. Now everything works and great brakes. I had to adjust the new unloader to the correct pressure for the FLU, which took about 5 minutes. If you take any air lines / fitting apart, be very careful as the fittings break very easily.

 

[Speedwoble]

If he had had trouble bleeding the brakes, I would be suspicious of the master cylinder. Many of these had issues with water in the brake system and because dot five brake fluid does not absorb the water, it will pool in the bottom of the master cylinder and corrode it. Obviously a master cylinder that doesn’t seal will allow the pedal to go to the floor as if it wasn’t bled.
I rigged up a pressure bleeder to make bleeding the brakes easy.

 

[319cssb]

I want to have a closer look at the master cylinder today. I’ll check the TM as to what normal air pressure should be and start to look into where things leak exactly.
speed woble I was also going to rig up some pressure bleeder, kind of like you’ve described.
what if I take A particular line off at the master cylinder and push fluid backwards toward the master and see what comes out? The thought is that if there is crud in the line, it will probably be easier to come out the top than through the bleeder. Just a thought.
The air leaks is just the first objective. There is about 50 to go. But I got to focus on each before opening the next Can of worms.
I talked to the PO and at least he didn’t mix brake fluids.

 

[Speedwoble]

I want to have a closer look at the master cylinder today. I’ll check the TM as to what normal air pressure should be and start to look into where things leak exactly.
speed woble I was also going to rig up some pressure bleeder, kind of like you’ve described.
what if I take A particular line off at the master cylinder and push fluid backwards toward the master and see what comes out? The thought is that if there is crud in the line, it will probably be easier to come out the top than through the bleeder. Just a thought.
The air leaks is just the first objective. There is about 50 to go. But I got to focus on each before opening the next Can of worms.
I talked to the PO and at least he didn’t mix brake fluids.

Certainly good the prior owner didn’t mix fluids! You can usually find mil surplus purple DOT 5 for reasonable prices in gallon quantities. If you buy it by the pint at an auto part store, it gets expensive.

My second FLU had water in the system that settled in the U bends by the front calipers. First drive in freezing weather and the brakes locked up after 1/2 mile and wouldn’t move until the heat from the caliper conducted down the line and melted the ice!

I see what you are saying about back flushing the system. Not a bad idea, but you are fighting gravity.
Here is a post on my pressure bleeder before I got cynical and stopped posting long descriptions. https://www.steelsoldiers.com/threads/flu419-see-hmmh-hme-owners-group.115476/post-2008572

 

[Mullaney]

The previous owner said he couldn’t get the brakes to bleed . So that there are no breaks. I noticed that when I run the truck, it doesn’t build over 70 psi in air pressure. There are a bunch of air leaks going on. It’s raining cats and dogs today so I didn’t get to do much but get the truck off of the trailer
View attachment 857812

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Congratulations on your new toy!
She definitely looks good from here...

 

[319cssb]

.
Congratulations on your new toy!
She definitely looks good from here...

Looks good from here… being wet from the rain.

 

[319cssb]

I’ve collected some parts from the floorboard. Looks there are some rubber bushings, I wonder if they are supposed to go on the fuel tank straps.

 

[Speedwoble]

I’ve collected some parts from the floorboard. Looks there are some rubber bushings, I wonder if they are supposed to go on the fuel tank straps.

I spy rubber bushings I suspect from the tension straps on the bed, a cut chain link from the military anti-theft, a battery tiedown, a battery lug insulator/cover.
I’m not sure about the bolts. You might check the cab mounts.

 

[Guyfang]

Battery hold down J bolt.
Broken battery hold down J bolt.
The fat rubber bushings and washers look like gen set shock Isolators.
the 4 fat bolts and washers look like gen set hold down gear.

 

[319cssb]

in many instances before, finding lose bolts and things give a good indication what needs to be fixed on a newly bought vehicle.
So I never just toss stuff out and disregard it.

 

[319cssb]

Is the normal air pressure around 70psi? The way the connections are, it doesn’t look like they could support much more than that.
Also I’m wondering if anyone swapped them for push in fittings?

 

[glcaines]

The cut-out pressure should be 106 PSI.

 

[319cssb]

has anyone swapped the fittings for push in hose fittings?

 

[glcaines]

Which fittings are you wanting to switch out?

 

[319cssb]

I saw some of the airlines appear to be pressfit. I wonder if it’s feasible to swap them out.

 

[glcaines]

I personally wouldn't touch anything that isn't leaking or plugged up. I replaced my 10mm crossover pipe that was corroded solid with a new 10mm 316 stainless tube and some dedicated Mercedes fitting on that line and the unloader. Other than that, I haven't replaced or touched any air lines and I don't have any leaks. I did replace the couplers on the two hydraulic tool lines that were severely corroded. I replaced them with new stainless steel Parker connectors I found on Ebay real cheap.

 

[319cssb]

Solid advise , glcaines. As they say if it ain’t broke…
I got plenty to fix as it is . I don’t need to search for fixable stuffs

 

[319cssb]

I’ve been trying for the most part of the day to bleed the brakes. I got a sprayer and filled it with a gallon of purple dot 5. Went to the master cylinder bleed nipples and connected the sprayer. Went to the rear tire and opened the bleed screw and … nothing. Cleaned out the bleed screw- no result. Went on the pass side by the torque tube and there is , what looks to me like a proportionate valve with a bleed nipple. I got fluid to come out of there. With a bunch of gunk. Bleed it until I got fresh fluid. I connected the pressure bleeder to the bleed screw on the rear wheel and I get fluid coming from the fitting by the brake caliper. I cracked the fitting by the axle open and I was also able to get fluid from there. But not from the master all the way back to the wheel.
The tm talks about a test port on the driver side. I can see it but cans acess it, do I have to have the cab up to get to it?