Where to service drum brakes on 1989 MB 1017A?

[gvvaughan]

Thanks for the manuals link. Purchased! I don't have a windows machine, but I have some intel macs in the loft which I can probably get Windows installed onto, and in the worst case any decent shop will have suitable laptops that can run it. Super useful

I'm also far from a mechanic, but I do most of the non-electrical work on my own motorcycle and pickup (often with the aid of youtube)... part of the attraction of a non-electronic vehicle is that I will be able to learn my way around it and do maintenance myself. At least once I have space to work on it and have collected the necessary tools.

Back to the brakes: hopefully it is something not prohibitvely expensive, but probably more than a spring since everything rides great even up to highway speeds as long as I don't touch the brakes. With luck it will be a bent shoe and not need the drums replaced, but thats to everyone else on this thread I found an enthusiastic shop who have a fenced yard to hold the truck while waiting for parts, and a reputable tow company to get it there. I've been using Eurotech to import air filters, oil filters and even a replacement for the cracked windshield, and they've been awesome - so it's only the wait and the cost I'll have to swallow.

Thanks for the air brakes info too. This is the first vehicle I have driven, let alone owned, with an air brake system so all of that is totally new to me -- save the previous owner talking me through the startup procedure and recommending depressing the saftey valves to blow some air out of the tanks after parking to minimize condensation and rust.

And extra gratitude to everyone who replied on this thread... I've gone from despair at having no idea how to get past my truck being stuck at a shop who don't really know how to or want to get everything working, to excited to have the info and contacts to get back on the road. Thank you all so much!

 

[Blowby]

Gary sorry to hear about your issues,and hopefully you come up with a solution.We are fairly new owners of a 93 1224 so from what I can see your brakes are similar to ours.
Am following along as I am also learning from your unfortunate experience.
We are also very close to you up in Truckee if you get by this way.
Roger

 

[gvvaughan]

Gary sorry to hear about your issues,and hopefully you come up with a solution.We are fairly new owners of a 93 1224 so from what I can see your brakes are similar to ours.
Am following along as I am also learning from your unfortunate experience.
We are also very close to you up in Truckee if you get by this way.
Roger

Hi Roger,

1224 is definitely a better chassis than the 1017, especially if you have a turbo and plan to be able to cold start at high altitude. Since buying mine, I've learned that a good rule of thumb is that you really want at least 20hp per ton... prior to the habitat refurb, I was north of 25,000lbs on the CAT scales with full diesel and water tanks, and any kind of long gradient on the freeway has me in 4th gear at 35mph, and pulling over to let traffic pass on a one lane steep incline is not an option unless I plan to finish the climb at 5mph in the crawler gear. The habitat refurb has replaced all of the Alder cabinetry with honeycomb fibre composite, which I hope will shed at least 1000lbs, and I don't fill the diesel tanks anymore if there are any hills en route. I'm looking forward to getting back on the scales to see how much lighter I am after I'm back in running order. If hills are still a battle, I'll probably be looking to install a turbo, and perhaps a gear splitter or something to have another ratio avaiable between 4th and 5th.

Current plan is to arrange a tow from the current shop to the one who is happy to work on it, wait for parts, and maybe early next year take a week long shakedown trip for the habitat upgrades in case anything needs attention before heading home to AZ. Would be great to meet up with any other owners in NorCal once I'm back on the road. I'll PM you when that happens

Cheers,
Gary

 

[Sitec]

Hi Gary.

Just read through this thread. The vibration you describe could have been caused by dragging shoes. If the rear brake shoes were not fully released when your truck was towed to the workshop, there would have been heat buildup from the binding shoes on the drum whilst in tow. When arriving at the workshop, and your truck stops moving, the rear brake shoes then sit applied to the now very hot drums in two places on the drum's circumference. As the drum cools, the area that the shoes are touching cools at a slower rate than the area where the shoes are not touching. This causes the drum to become mis-shapen, (in effect turning it slightly egg shaped!). Then when you turn up to a now cold truck a few days later, turn the key and drive off down the road, the first time you apply the brakes you get a real vibration. This will be noticeably worse at slow speeds or more of a 'rumble' under braking at high speeds. If this sounds like what you are experiencing, then the rear drums are now 'out of round', and will need machining or replacing. Sometimes this is very hard to see even if you can view the drum spinning. The only real way to be sure is to remove the drums, and rotate them slowly in a lathe with a dial gauge set up on the inside face. This will tell you if they're out of round.

Keep us updated. Ours is a 1222a which has Hub Reduction in the rear, so I think the brake setup is a little different.

One thing I will say though, is always treat the brake boosters (large thing that looks like a big saucepan with a rod coming out) with the utmost respect. There is a huge spring in there under a lot of pressure. Air pressure compresses this spring releasing the brakes. As Jon said earlier, winding the centre threaded bolt out (compressing the spring) releases the brakes if air is not available. Just never try to take this thing apart without knowing exactly what is in there. They can act like a 20 tonne jack in the box in the wrong hands!

 

[Neil]

1224 is definitely a better chassis than the 1017, especially if you have a turbo and plan to be able to cold start at high altitude.

Not sure how high you are going but I have cold started mine at over 5000m ( 16500 ft ) at minus 25c.

Does yours not have a turbo, doesn't it have the OM352A engine

Neil

 

[gvvaughan]

Hi Sitec,

I'm also leaning towards warped drums and/or bent shoes being the problem given the circumstances that led to the issue. Interesting how you describe letting the air out will let the shoes contact the drum and lead to this issue as everything cools unevenly though. Also the diesel shop the performed the service swear that with the truck lifted off the ground and the wheels off, they can see the vibration in the rear when the brakes are applied, but can't see anything obvious out of place otherwise so the warping may be relatively minor.

Unfortunately I'm not in CA, so I wasn't able to see them try to diagnose the issue. I'm very interested to get it to the new shop who are more familiar with this type of truck to learn what needs to happen to get back on the road. I know the previous owner had the drums resurfaced a couple of years ago, so maybe I'll luck out and not have to wait for a fresh set of drums from Germany if they're not seriously warped...

Good advice about the brake boosters in case I'm ever in the position of needing to work on this myself one day! Thanks!

 

[gvvaughan]

Not sure how high you are going but I have cold started mine at over 5000m ( 16500 ft ) at minus 25c.

Does yours not have a turbo, doesn't it have the OM352A engine

Neil

I originally bought it with a plan to drive to the tip of South America (before COVID made borders more challenging), which does have some extremeley high altitude sections... there are roads in Chile and Argentina above 20,000ft. At best that trip is extremely delayed (not only by the unreasonably long refurb time), and I might even shelve that idea in favor of driving through Alaska and exploring the rest of the Northern US States that I haven't seen yet.

I could swear the previous owner told me that the engine was un-turboed, but looking at the specs for that model it is supposed to come with a 168bhp 6ltr 6 cylinder turboed OM352A. I'll have to take a look under the cab to be sure! If it does have a turbo, that would be great in respect of high altitude cold starts... and your successful 5000m cold start gives me a lot more confidence! Perhaps fitting a bigger turbo will be the easiest route to try and get some more power out of that engine?

 

[theangrychicken]

gvvaughan, I am also trying to get that manual through ebay and I"m a Mac user.
I reached out to the seller who stated you can use a app called, "unarchiver".

I stopped by Betts today, they had me in/out pretty quick. They swapped out my leaf spring and air canister. They charged me for the u-bolts/nuts and 3 hours of labor. The cost was very reasonable and the work look fairly simply to do if you have the tools for it.

If you end up needing new shoes or other parts, consider hitting up Hans at https://unimogcanada.com I've been emailing them and they can source shoes. Hans has been very responsive and helpful.

I'm currently in the Bay Area. I've been combating my alternator mounting and I just replaced a lower mounting bolt for the 2nd time. That's when I noticed the bolt that secures the tension bolt to the engine had sheared off it's head. I think there is some flex that is shearing my bolts. I'm hoping to get that bolt tapped out and replaced ASAP. The tensioner is literally hanging on the threads. I was hoping to head to Tahoe this week, I'm happy to stop in Sac if I can be of any help.

Anyone happen to know the thread pitch and bolt length for the bolt that attaches the alternator tensioner to the engine? It's #44 in this file.

 

[Neil]

I originally bought it with a plan to drive to the tip of South America (before COVID made borders more challenging), which does have some extremeley high altitude sections... there are roads in Chile and Argentina above 20,000ft.

I have done this journey in ours

I crossed the Andes in Chile and Argentina at least 20 times and didn't see a road that high.

The highest we saw was about 5200m ( 17000 ft) and it did it no problem.

Mine is a basic set up and not modified.

If yours has the OM352A engine then it has a turbo

Neil

 

[gvvaughan]

I met with a tow truck driver to successfully move the rig to Betts in Sacramento, and the shop I was moving it from said that the shaking under braking was from the front end, and not the rear as I was originally told by the service desk, but that they had since repacked all the front bearings and now it was hard to feel any dragging below 40mph. I'm finding it hard to believe anything they tell me at this stage.

The new tow truck driver from College Oaks Towing (highly recommended after my great experience with them) asked me lots of questions about the previous tow, and the set up of the truck to figure out the safest way to move it. In addition to back feeding air to disengage the parking brake, and selecting neutral from the stick shift, he also put the diff in neutral (at least that's what I think the "O" selection means, as opposed to two parallel lines where I have always driven it, and two wavy lines which I haven't used?), and dropped a drive line at the rear transfer case so that spinning the rear wheels during the tow wouldn't spin the transmission at the front freely. He drove it a little in first gear at either end of the hookup too, and thinks the previous emergency tow damaged the transmission by leaving the drive lines hooked up even for just the mile and a half back to the first shop.

At Betts, they said they tend to agree, but were happy to check the alignment and weighting on the wheels, tires and brakes to rule out any possible issues there. Possibly the last shop also destroyed two of the tires by letting them go completely flat to the point the rig was tilted so far over that diesel spilled out of the filler tube at the top of he tanks on that side. I'll call them in a couple of days to see what they determined, and pay them for the diagnosis...but it seems likely I'll be billing the previous shop for replacement tires, and asking my insurance to pay for repairing or replacing the transmission if the driver they sent last time caused the shaking problem.

In all fairness, for most of the time I've owned it I had noticed one tire was losing a few psi per week, but would refill to 110psi every 2 weeks for drive days and was just expecting to need a valve replaced at the next service. I looked up the codes on the tires, and even though they have no more than 20k miles on them and a ton of tread remaining, they were manufactured in 2009... so now I suspect the rubber is dry and stiff from age, and I was probably leaking from the bead. Having the full weight of the truck distort the side walls enough to pop them off the bead is a good sign that I should replace them all now IMHO anyway.

Anyone agree or disagree with some or all of the above?

 

[theangrychicken]

Did your issue here get resolved?


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[gvvaughan]

Hi! Thanks for asking

And yes -- more or less: Betts diagnosed everything properly for me, and found nothing wrong except one of the front drums is slightly warped. The manual says that within certain tolerances, the drums can be resurfaced no more than 3 times. Since the warped drum looks original, and I know the previous owner resurfaced the front drums just prior to selling to me, I decided to get a new front pair of drums shipped from Germany.

Once they're installed, we're all confident everything will run great again at highway speeds. That's probably a still a few weeks out, after which I want to take the truck back to the refurb shop to take care of some small issues and will most likely camp out in the area for a couple of weeks so I'm close to the shop if anything else comes up.

I still have absolutely no idea why it was driving perfectly smoothly all the way through the gears up to 55mph prior to the original tow, but started shaking dangerously under braking after that tow, especially at the front!

Eventually, I'll be driving home through Bakersfield, and would love to meet up if we can find a convenient time and place....

 

[theangrychicken]

That’s good to hear and I’m hoping that resolves your issue. Replacing drums vs transmission parts sounds like a better option!


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[where_the_heffalump_roams]

Is Betts in Sacramento helping you with this?
I have a wedge actuator that failed and a new one is en route to Yuba City (close to Sacramento). I was thinking Betts in Sacramento could help install it. But I just called them and they stated they wouldn't work on trucks like ours (although they San Leandro site helped me).

 

[gvvaughan]

Howdy! Yep, Betts of Sacramento. They seem to specialize in brakes and service, but were willing to take my rig across the street for diagnosis of any transmission issues (but didn't need to in the end), and they took my drums to another shop to have the alignment checked. They have been extremely helpful and friendly through the whole process. HTH!