On the way home from work today, at about 60 MPH, a very loud squeal startled me back to reality. I got off the gas and started coasting, and the squeal stopped after about 10-15 seconds. I pulled to the shoulder and popped the hood, everything looked to be intact. I got home, changed into grubs and started checking things out better.

All the belts were intact, the engine never got warmer than about 180 F, and there was no oil/fluids sprayed about the engine compartment. I have been having a mysterious growl on occasion from the steering pump, and suspected that it had taken a hike.

I put a box wrench on the pully nut and tried to turn the pully both clockwise and counter clockwise. I could not muster enough umpph to move it the slightest.

Seems to me the pump has seized, and I apparently got lucky that I didn't throw the belts since they also drive the water pump. Am I correct that this sounds like a seized steering pump? Can I possibly rebuild it or am I better off finding a good used one from a dismantler and rebuilding it?

No way will I be able to get one from the dealer, they want almost $700.00 for a re-manufactured one, by the time I throw in tax it'd be well beyond seven bills.

Thanks for the help.

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Mike Tangas
73 280 SEL 4.5

Pully should move freely. You are correct. The pump has seized. Maybe the folks here can help you. You can try Atlanta-Stuttgart Auto Parts. They have tons of old MBZ parts etc. The number is 1-800-635-1445. Punch in 1110 for extension and you'll get Dave. I think Benzmac has a couple of other sources as well.

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Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 04-26-2000).]

Thanks for the confirmation of my suspicions. I have never had a vehicle with double belts on the steering pump, and wasn't sure if the extra tension and surface area of belt to pully would cause enough resistance to prevent me from turning the pully.

Guess I'll be driving the Suburban till I get the Benz fixed. It gets the same mileage, but costs a whole lot more to fill up.

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Mike Tangas
73 280 SEL 4.5

Did you try turning the powersteering pulley with the belts on or off? Also am I correct in saying that you are not suppose to try and turn any accessory from their pulley nut if they are still connected to the crank shaft pulley via a belt. You must turn everything from the crank shaft pulley only in the direction of rotation of the engine. Turning it in the opposite direction will damage the engine.

You can watch the pulley turn if you have the engine running or you can remove the double belts on the power steering pump and turn the pulley by hand to check for "free" rotation in either direction. It is impossible to turn these things with the belts on and tensioned. You could easily break off the pulley nut.

Just clarifying wether you tried turning it it with the belt on or off...good luck with your diagnosis.

Nolan

Since everything was hot, and I was riding herd on the kids, I tried without removing the belts. There was a slight amount of slack in them and figured the pully would slip with a little pressure. No movement at the pully, nor belts.

I agree it is not advisable to try to turn the engine by accessory drives, however, in this case due to the slack, I felt the pully would slip before the crank moved.

Not five minutes ago, after the car had cooled for about four hours, I started the engine and the pump was turning. Then, again tried to turn the pully with a wrench. There was enough slack and I could move the pully about 1/4 inch with out much effort, due to the pully slipping under the belt.

After taking a second look, here's what I think is happening: For whatever reason, the pump impeller dragging, worn bearing or something else, the pump overheated. The excess heat caused internal parts swelling which seized the pump. The metal cooled, the internal parts returned to proper dimensions and the pump freed up.

When I first popped the hood, and began checking the pump, the pump was *very* hot. Today was a hot day here, but not that hot. The pump was too hot to touch after the short 10 mile drive home, more than likely internal heat build-up from the pump failing. I could test the thoery by driving to work it tomorrow, but then I'd stand the chance of losing the belts and toasting a great running 117 engine.

I guess after 27 years, I can expect the pump to fail. By the condition of the surrounding area and mounting bracket, it appears this is the original pump.

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Mike Tangas
73 280 SEL 4.5



[This message has been edited by MikeTangas (edited 04-27-2000).]

These don't fail. It will not turn without the belts being off of it completely. Don't waste money, be sure. The only way these fail, is when they are over tightened severely/

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

There have been discussions about turning engines via crank bolts before on this BB and I thought I would recap some of the logic behind this policy to make sure people know it is fact, not fiction.

The crank gear is the drive gear, and the cam gear is the driven gear. A chain is strictly a tension load carrier. You can not "push" a chain or rope, only pull it. The drive chain design is such that the driving side of the chain is in tension, as it should be. The chain tensioner, or belt tensioner on japanese cars, is on the unlaoded or idle side. When you attempt to rotate in the wrong direction, it puts the idle side in tension, causing the tensioning device to spring back, and then the chain or belt jumps a tooth. The rest is history. Rotating in the correct direction, it will go hundreds of thousands of miles whether driven by the pistons or your rachet wrench.

Hope this helps!

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Deezel
87 300TDT
150,000 miles

Rest assured that trying to turn the pump with the belts on was only a quick shadetree check of the pump. The belts will be coming off for a more thourough check. I don't think the squeal was due to loose belts, they have about 3/8 inch deflection, max.

As soon as I got in from work today I went straight to the garage and checked the fluid (steering fluid, not ATF). The car had been sitting for almost 24 hours, and the fluid appeared to be slightly pink. Looked like the color was due to air bubbles, which were still suspended in the fluid. I find no leaks or drips coming from the pressure or return line. Not sure where air would be getting in the system.

When I pull the belts and check the pump closer, I'll pass on my findings.



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Mike Tangas
73 280 SEL 4.5

OK y'all, here's the latest info:

I pulled the belts today. I ended up having to pull the fan in order to get into one nut, but got it loose enough to get the belts free. The pump turns with some resistance, not exactly freely though.

As I worked the pully, I noticed there was *some* play for and aft. When I pulled toward the radiator while turning the pully, the pully and shaft came freely out until hitting the fan shroud, which is at least an inch of travel. When the pully is in the out position, the resistance is greatly increased to the point I cannot turn the pully.

I have siphoned off most of the fluid from the resevoir, leaving a small amount at the bottom. When I turn the pully, I can hear the innerds working, I do not hear, or feel any grinding. I guess my heat theory was incorrect .

Does this pump sound as if it is still rebuildable, or does that much for and aft play mean it's beyond rebuilding?

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Mike Tangas
73 280 SEL 4.5

[This message has been edited by MikeTangas (edited 05-01-2000).]

Mike, the pulley shaft should not be that loose. At least not an inch or greater coming out of the pump casing. Donnie knows these parts much better than I, but I would say, that by your description, something inside the pump is broken or a retainer nut has come loose. I would try and locate a used pump. I have no idea where you could get parts for this. Also, it seems apparent that there is some internal damage.

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Jeff L
1987 300e
1989 300e
1987 BMW 325

Mike,

One of your best bets for finding one of these pumps would be posting a wanted ad on the Shop and Swap classifieds on this site.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

You can try Atlanta-Stuttgart Auto Parts. They have tons of old MBZ parts etc. The number is 1-800-635-1445. Punch in 1110 for extension and you'll get Dave.

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Jeff L
1987 300e
1989 300e
1987 BMW 325

Get a used pump and be done with it. It sounds as if the pump has lost a shaft. (I think that the belts may have been overtightned to cause this)

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I am searching for a pump now. I am trying locally (So Cal area) first, if no luck then I'll try Jeffsr's friend Dave atAtlanta-Stuttgart.

As far as the belts being over tightened, I have never adjusted them since I bought the car. They had approximately 3/8 inch deflection, which I felt was OK. What amount of deflection should they have? I ask so I can adjust properly once I have a replacement pump.

I'll be working on getting the old one out this evening, if nothing else needs my attention.

Thanks for all the replies and advice.

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Mike Tangas
73 280 SEL 4.5

That pump was the same for many years the ones that had the reservoir attached were interchangable with the ones that didn't.

They should be dime a dozen. If they all feel they are special let me know I probably have 10-50 laying around here. Except for your failure they hardly ever do anything wrong but leak. I have seen 3-4 do what your pump did. It has to really wear out. I forget how it does it but its really worn out when it occurs.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician