OM603: Vacuum pump explosion, bearing intact! Injection Pump Timing device wrecked - PeachParts Mercedes-Benz Forum

gsxr · #1 08-24-2008, 08:45 PM

While at the dyno this morning (more on those results in a different thread), after the second pull the dyno operator mentioned a light ticking noise from the engine. It was pretty faint so I said "nah, that's ok" and we did a third pull. After this pull, the noise was much worse - still couldn't tell what it was, but the engine was running ok. Upon backing it out of the shop, the power assist for the brakes went dead, then when I parked it the engine wouldn't shut off. D'oh... obvious vac pump failure. So I towed it home, pushed it into the garage (with some help from some sympathetic neighbors), and tore things apart for a look-see. Check out the photos below. OUCH!

I thought I had replaced this vac pump sometime during my ownership of the car, but after reviewing my records, it appears I had not... because it was replaced by the previous owner 2 years before I bought the car. Actually, the pump was first replaced in 1993 @ 117kmi, and replaced again in 1995 at 152kmi (not sure why the second pump failed in such a short period of time). I purchased the car in 1997 with 187kmi on the clock and a 2-year old Pierburg pump. Well, a mere 141kmi later, the pump kerploded magnificently. I'll have to drain the oil pan and pull the side sump to (hopefully) fish out the rest of the debris... there's a big chunk o' pump missing, that is nowhere to be found right now.

Worse yet... I had recently replaced the timing device with a shiny new one from the dealer ($300 list price) when my timing cover failed 3 years ago. I don't think I'll be able to re-use it.

There goes another $250+ out the window. *sigh*

Anyway... has anyone seen a pump failure like this before? The bearing is fully intact, and the pump was not leaking one drop of oil externally. There was no signs of impending failure, just BOOM rattle rattle tinkle ping poof.

David Wilson · #2 08-24-2008, 08:56 PM

Wow! I am so glad you guys "strongly suggested" that I replace my original pump. Next weekend.

Bio300TDTdriver · #3 08-24-2008, 09:01 PM

So I guess there is more to worry about than just the ball bearings coming out.

I have new squeak in the last week, but can't seem to locate a source I guess I'll listen to the vacuum pump in the morning.

Good luck find all the pieces.

Chris

pawoSD · #4 08-24-2008, 09:04 PM

Makes you wonder if just putting an electric vacuum pump on these cars is more safe/reliable....just slap a cover/gasket over the pump's former location, and upgrade the alternator....slap in an electric pump, and go. It almost seems worth it!

gsxr · #5 08-24-2008, 09:17 PM

Quote:

Originally Posted by pawoSD

Makes you wonder if just putting an electric vacuum pump on these cars is more safe/reliable....just slap a cover/gasket over the pump's former location, and upgrade the alternator....slap in an electric pump, and go. It almost seems worth it!

Sure is tempting, that's for sure. I wonder what's available in the aftermarket that would supply an appropriate amount of vacuum.

sixto · #6 08-24-2008, 09:25 PM

Dave, is plunger seized? Can you compare the force required to compress the plunger in the two pumps in front of you?

Looks like the pivot shaft is retained by a couple of circlips. I'm surpised they used circlips in a situation where one part can move relative to the other.

Did the dam gasket catch anything?

GM 6.5 IDIs have a belt driven vacuum pump. Maybe one can be grafted inplace of a wagon tandem pump for non-SLS applications.

Sixto
87 300D

sixto · #7 08-24-2008, 09:27 PM

Electric pump for an EV conversion should do the trick.

Sixto
87 300D

gsxr · #8 08-24-2008, 09:52 PM

Sixto, I haven't tried to compare the plunger pressure, but on a new/good pump it takes pretty massive pressure to budge it at all. I found one of the circlips, but not the other. I also need to locate the large piece of missing bracket (left side), I found the small piece (right side). The dam gasket had some shavings in it, but that's about it. There's a fair amount of shavings all over the place right now.

I was debating trying to salvage the oil (3kmi on Delvac-1) but I think it would be better to toss it due to the amount of metal lost. OTOH, I'm half tempted to strain it and re-use it for another 100 miles as a "flush" before changing the oil & filter. I suspect there are a lot of metal bits floating inside the timing cover area.

Zeitgeist · #9 08-24-2008, 09:59 PM

Years ago I had a '73 220D with a VP that experienced a very similar failure mode--everything just sorta lost interest in remaining intact.

I think I'd pull the side cover off the pan, and then run kerosene down that chain vault until all the shavings washed out. Bummer dude. Now I have another paranoia vector

pawoSD · #10 08-24-2008, 10:02 PM

Quote:

Originally Posted by sixto

Electric pump for an EV conversion should do the trick.

Sixto
87 300D

Thats what I was thinking, then the worst that can happen if it fails is a loss of vacuum and maybe a blown fuse.

compress ignite · #11 08-25-2008, 12:10 AM

Quote:

Originally Posted by sixto

Electric pump for an EV conversion should do the trick.

Sixto
87 300D

Please elongate the short hand "EV", Thanks!
(I don't know what you're referring to)

GSXR,

Scary,Scary.Scary. How many RPMs was the engine subjected to?

My 100K miles,"replace" list just grew.
Chains,Sprockets,Tensioner,Timer,VP.

I wonder if Pierburg is saving money on castings? (or if it was the C-clip?)

gsxr · #12 08-25-2008, 01:24 AM

Indicated max RPM on the tach, and dyno sheet, was approx 5400rpm. That's within factory specs (on the high side, but still within spec). The Crazy Finns have pushed these engines past 5500 without pump failures, so I don't think it was necessarily the RPM at fault. But if my pump was on the way out (hairline fracture in the casting?), the high RPM likely hastened its demise.

pawoSD · #13 08-25-2008, 01:44 AM

Hmmm....are the 617 pumps more durable than the 603 pumps? There seem to be less reports of them failing, and many more people here have 617's than 603's.....not to mention the only ones I've heard of failing were on engines with like 400k+ on them....

5400rpm!? Wow.....Even to the floor between shifts my 617 never likes to go much over 4000-4200 or so....if I really push it I can get to 4500 in third before it wants to shift (unless I keep it from doing it with the shifter)....I'd never make my poor engine go much higher than that though, too paranoid. I am usually pretty gentle (and don't go much over 3500)

Diesel911 · #14 08-25-2008, 02:03 AM

Ebay has several types of electric Vacuum Pumps for vehicles selling on Ebay. But you need to be careful as some of the Ford type vacuum pumps people are selling are not rated for Power Brake Boosters.
The one that are sell for close to $300 and have a pressure sensitive relay to shut the pump of when the highest vacuum is reached.

Also, member Stevo believes his vacuum pump failure was caused by too much play from a worn IP Timer Bushing. When you replace the IP Timer you might want to check the Bushing clearances.

Excellent photography.

turbobenz · #15 08-25-2008, 02:31 AM

long live the 617