My daughter was driving her car the other night and experienced a clunk/bang and the engine lost power. I discovered that the vacuum pump housing on the right front of the diesel engine (at 3 o'clock) is cracked right by the bolt head (located at about 2 o'clock on the pump) that protrudes and creates a "shoulder" there (I could observe some oil leaking out of it but nothing excessive as she stopped very shortly after it occurred).

I'll remove it this weekend and try and determine what happened. I can see from pictures and diagrams that it has a roller that must ride on a lobe or some other surface to power it. I'm hoping that it is simple metal fatigue and not something worse. It ran until she pulled over and stopped it. I was not able to find this type of problem described on this forum or the vintage forum., Anyone have experience with this and would I be better off rebuilding one or trying to buy a "new" one?

When you pull it off you'll see where it drives - sort of a ramp arrangement. It's likely that the broken housing is a result and not the initial failure so look carefully for anything that could make the housing fail (a bound bearing, etc.). I'm pretty sure that there's a thread on here for rebuilding the vacuum pump and that might help in this repair.

I'm replacing my vacuum pump with a VW electric pump but I don't know if that's appropriate for vacuum assist brakes - I just need it for engine shut off.

Dan

Thanks Dan, that helps. I'm concerned it may be a symptom of a greater problem...just hoping for metal fatigue

I have seen this many times.

If you can post pictures, a diagnosis / damage estimate may be possible.


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Dynamometer.
Heat exchanger durability.
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1983 300D
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After the Vacuum Pump is off do not crank the Engine with the Starter. Crank it by hand several complete revolutions and see if anthing hangs up as you turn it. Removing the Glow Plugs will make it easier to turn.

Remove, your Valve Covor and inspect the Aluminum Camshaft Bearing Towers for cracks and the Camshaft itself.

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84 300D, 82 Volvo 244Gl Diesel

I had the same problem, but I bought the vehicle with this problem. Previous owner described the same situation, loud bang, loss of power, pulled over but it never started again and had it towed. When I got the vehicle the pump was off and an electric vacuum was installed. I also got a bag with all the pieces and mysteriously enough there was a few metal pieces missing. Later to be found inside the engine. The bearings destroyed themselves causing the rod to disintegrate and rip a hole in the diaphragm. All the metal went inside the engine and caused the chain to skip a tooth. Metal was found in the oil pan and in the pickup screen. This is a worst case scenario and what happened to me.I do not mean to scare you. If you remove the pump do as Diesel911 suggested and hand crank the engine over to make sure it doesn't bind. Do a visual check on the pump and make sure all the pieces are there. I would maybe even remove the oil pan to see if there is any debris. Pictures of the damage would help.

As for rebuild kits go I do not know whether your pump is a piston type or a diaphragm type. If a diaphragm the only thing a rebuild kit would include is the diaphragm and valves. Not the housing. New pumps are had at a premium price and last I checked I was quoted around $500. I think only 1 or 2 manufacturers even make them. Your best option is sourcing a used pump. I have a few piston and diaphragm pump lying around.

Here is is the extent of my damage.

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More pictures. Hope yours is not as bad. To determine whether your pump is a piston or diaphragm pump look for how many lines come out of it. 1 is piston, 2 is diaphragm.

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It looks like your timing device came apart.

You need a good used vacuum pump and timing device.

PM your VIN# so I can verify correct parts options..

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__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

That is the extent of my damage not the OP. I was giving an example of my experience.

I mentioned this over on Benzworld where I go by 300Dman. If the Vacuum Pump Housing is cracked I would say that there is nothing to rebuild.

If the Housing was OK the price of the Diaphragm end is cheap but the price of the Arm Assembly is not.

On the Piston Type Vacuum Pumps if you do the complete rebuild and get both Parts Kits it will cost as much as a New Vacuum Pump and you have no warranty.

If the Bushing on the Timer is worn out and allows the Timer too much end play on the Piston type Pumps that can and has ruin a new Vacuum Pump. I am not sure if that can happen on the Diaphragm type Vacuum Pumps.

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84 300D, 82 Volvo 244Gl Diesel

As soon as the block off plate is ready I'll have a diaphragm style pump available. All I can say is that worked well the last time the donor car ran so it should be OK. PM me and we can make a deal if that's what you need - I don't need a lot for it.

That reminds me - I need to PM Greazzer and see how those plates are coming.

Dan

It took a bit longer to get out because I insisted that my daughter take it out herself. I expect she will have to work on it when she is at college and I'm not nearby. I didn't hear any parts drop except the broken portion of the housing.

I poured 6 small ball bearings and the remaining parts in the picture out of the main housing. I'm going to take a rare earth magnet to the block area tonight.

I expect that I check the play of the cam end that drives it by gently pulling up on it.

Looks like I'm in the market for a housing. If the vacuum hose fitting on a new one is not exact, I expect I can swap the one on this housing for the other. Looks like the same bolt pattern on all those I've seen.

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Thanks for the help. It is in pieces. Wow. Never had such a clear failure before.

Since I don't drive it, I don't know if it was making noise before it failed. Sometimes it is hard to tell on the old diesels.

MY Question on Timing Chain Failure
Who has or knows someone that has experienced a timing chain breakage/failure? - PeachParts Mercedes ShopForum

My question What in particular causes vacuum pump failure?
What in particular causes vacuum pump failure?

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84 300D, 82 Volvo 244Gl Diesel