Rear brakes

[Wolvesamongus]

This is not what I wanted to see today, removed stub axle and plenty oil came out no grease on the outer bearing just oil as shown and very little on the inner one and the hub that goes over the spindle is plenty oil again as shown, what's going on?

Regards----Kim

[Admin]

Looks normal to me. In most trucks the (driven) rear axle (differential and wheel bearings) is lubricated by the same oil, which floats around freely, locked in by oil seals. That's why there's always some oil leaking out when you remove the axle shaft(s).

Be careful not to damage the oil seals when you re-assemble it.

[Wolvesamongus]

Thanks Eernst, you put my mind at rest got stressed a bit, thinking about it logically got to be right a big learning curve to me this Bus but the only way is to to it, so put a little axle oil on that spindle when the hub is back on before replacing washers nuts etc I guess.
Use blue sealant for the stub axle gasket yes? There is another thin band of set hard sealant around and a little away from the stub axle shaft what is used here?
I will jack it much higher for the other side to stop so much oil coming out next time,(learning)
Thanks again Regards-----Kim

[Admin]

I thought (but I'm not 100 % sure) the Düsseldorfers only had a paper gasket in the rear hubs, but I don't think a thin layer of fluid gasket will do any harm.... DVIII wil be able to tell if I'm right.

[Wolvesamongus]

Thanks Yes it was a gasket but I doubt if they are available now, yes David is the man better known as Trig, (ask him)

Regards----Kim

[Admin]

If you are a perfectionist and want to do it extremely well, you buy a sheet op gasket paper (although thick drawing paper will do as well), cut it in the right shape (slightly too big) and punch out the holes...
I last did that when I was 16 years old, for my moped

[Wolvesamongus]

Sixteen long time since for me lol, yes done that many times in the past but bit of a funny shape that one kinda wide around where the studs come through and very narrow in between, I'm sure I have seen a vid of someone using Blue gasket sealer.

Regards----Kim

[Hanomaad]

I've used blue liquid sealant for the stub axle gasket and no oil has gotten out there. Oil did get out from one side as there was too much in the differential, but it got out via the little hole in the hub that's meant to let that out.

What I learned from Franz in the videos is to put some differential oil inside the axle shaft before placing back the stub axles and everything else.

[Arno Z]

I've also used liquid seal for closing up the axle. But do mind some of those have a working temperature and it may be to cold for them to be used in current weather conditions (except of course if you are working in a heated area). Also make sure to degrease both areas thoroughly.

Instead of using differential oil on the gasket, i used plain grease on the bearing stub to prevent the gasket from damaging while reassembling. Which is just a matter of opinion a guess. Just be aware the gaskets are fragile. Do inspect them prior to reassembling, they may have been damaged from the disassembly.

Also, after your first drive check the flow-off tubes for leakage. They are able to catch the oil from minor leakage, but will not cope when you continue driving with a damaged seal.

[Wolvesamongus]

Thanks guys blue it is then, the hub came of easy and straight so seal should be OK looks good but will take great care on reassembly, am I right in saying the torque for the stub axle nuts on 508d are 41psi?
And the oil is hypoid SAE 90.
Regards----kim

[Hanomaad]

What I poured into my differential: Kroon-Oil Gearlube GL-5 80W-90

And this is where you can find the required torque for the nuts:

viewtopic.php?f=23&t=7458&p=71616&hilit ... ent#p71616

The above is in Nm. I think you mean pound-feet instead of PSI? In that case, it should be around 47.5*0.7375621=35 pound-feet (approx.). Not a lot.

[Wolvesamongus]

Psi lol it was early, thanks for the link got it, all done one side (man those springs) the one thing I didn't like was the hammer and chisel on the flange nut you can't get a feel for how tight you are pulling in I guess just keep going until there is no in out movement on the hub then back of a little, got to find me the right tool, I think when I do the other side I'll make a pattern of the nut and get one made.

Regards-----kim

[Wolvesamongus]

Water, time and brake fluid, when you think it has stood still the best part of 27years, I think they needed doing.

[Admin]

Known fact that brakes in Düsseldorfers (even new ones) deteriorate from just standing still. One should drive a bit - maybe only one block - every few months.

[Wolvesamongus]

Good thing this is my everyday transport if that is the case.

Regards----Kim

[DVIII]

thats a rather odd statement , so only dusseldorfers have this quality to deteriorate on the brake system. this could be a scientific breaktrough , please Ernest , share this wisdom

[Admin]

Of course not only Dudos. Probably all hydraulic systems.
But the truck dealer where I have been customer (mainly for parts) since 1972 (Van den Braak in Veghel) has found time-corrosion in Dudo brake cylinders worse than in most other vehicles.
And then, many have a fire brigade or ambulance history, so have been standing still a lot. And many now are converted for recreational purposes, so are still standing still a lot.

[DVIII]

so are still standing still alot , that like , she sells seashell on the seashore . I'm still not convinced by your arguments
and what I do myself to prevent the halfaxle from sweating , i plaster the space full of grease before replacing the shaft. so the grease forms a dam

[listerdiesel]

I think that possibly Ernst was referring to the fact that a vehicle that gets driven daily will expel moisture around the brakes and inside the drums, oils will reach their working temperature and flow freely, and hygroscopic fluids like brake fluid don't absorb as much moisture than if they were standing still.

The axle on my 614D has a very neat little pigtail breather look above the diff on this picture:



Peter

[Admin]

I have somewhere in my shed a glass jar with two brake cylinders that are internally completely corroded (so that they could not be polished anymore) from a 26 year old 508 with 17.000 km on the odometer. In the workshop of my late friend's garage they have a big crate full.
Indeed it is moisture, but more inside the cylinders and not so much in the drums.

[DVIII]

we are mixing two things here, actually three . First , hydraulic brakes do have the problem to corrode the cilinders on the outside of the pistons , the pistons are aluminium and the cilinders are cast , without some proper protection , every time the cilinder works the air inside is replaced by new fresh moisture containing air . and it's more a matter of time , than mileage that causes the problem. Two air brake systems have no corrosion in the same way as hydraulic systems , and the picture on lister's is definitely a sole air brake system , the only hydraulics on his bus is in the clutch operating system. And last, the pigtail breather on the axle shown is only to prevent water and dirt coming into the axle body , an axle in use cools down and heats up under de force / friction during a ride and the air thats going in and out could cause a problem one day . the earlyer versions on the axle of MB were only provided with a small raincap . in a certain situation of serious rain during the ride , the watercloud under the truck can not so easy enter the axle body . on all terrain vehicles the breather line goes up to higher and dryer positions .

[Admin]

I think we completely agree on these three subjects.
One of the reasons I go for "full air" brakes, whenever possible.

[listerdiesel]

The 614D has vacuum assisted hydraulic brakes, the spring brake cylinders are for parking only. There is a vacuum pump on the engine and a 24V Knorr-Bremse compressor inside the chassis, with reservoir tanks etc etc. You can see the separate hydraulic lines running down the back of the diff housing.

Pictures of the 24V compressor:





The Cyan arrow marks the union that has a bad air leak, so I have to strip that down and work on it. The compressor runs as long as the engine is running, signalled by the alternator warning light I believe.

I should have made it more clear on the axle breather, that was in response to a separate issue to the brake cylinder rusting.

Our Discovery V8 has stainless steel pistons in the calipers, might be a thought to get some made for the wheel cylinders?

Peter

[DVIII]

holy mozes , thats what i call a serious daimler chrysler mess of a brake system , not that it does not what it's supposed to do , but for crying out loud , why vacuum and compressed air , I mean do not ever get stranded with a system like this , the'l skin you to the bone with all that special parts , guess it has ABS too . honest , since the russians have gave up taking over europe , the designers have a carte blanche for making it all particulary interesting . if I had to do the trick , the regular brake would also be air assisted . I like those disk brakes , but the way to get there knorr must be having a field day it must be the client who ordered it this way or the regulations on bustransport

[listerdiesel]

I don't know why MB went that route, but the parking brake was to meet secondary braking regulations I assume.

Most of the 814D system will fit, but you need the 814D hubs and discs and calipers and the larger wheels.

I think that one reservoir tank is just a dead end, it doesn't pass air on to anywhere else.

I have an 814D compressor, toying with the idea of replacing the electric pump at least, that little baby is a LOT of money if it goes wrong, and I don't see any other manufacturer using it.





There is no ABS on our chassis.

Peter