Different V-belts for E9 power steering?

Krzysztof

Krzysztof

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Hi,

Does anyone know why there are three different lengths (= BMW part numbers) for the V-belt for the same steering pump?

1. 32 41 1 268 687 9,5 X 1075
2. 32 41 1 268 688 9,5 X 1125
3. 32 42 1 711 067 9,5 X 900

It looks like - according to BMW catalog - they are not related to specific year or model. o_O
 
There were two belts that ran off of the water pump pulley. The 1075mm belt pulley was the original spec. BMW modified the pulleys to improve engine cooling somewhere in the production of our cars (not sure when), which then entailed the 1125 mm belt. I believe the water pump pulley diameters would be 134mm initally, with the updated pulley at 102mm.

Lastly, BMW changed to running the power steering pump off of the harmonic balancer pulley. The shortest belt was the one that ran off the harmonic balancer pulley.
 
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Another question which might be interesting for Others...

Is then the harmonic balancer wheel a good upgrade (if possible at all) for older models as it should make the engine operation less rough and possibly improve the lifetime of the belt, water pump and alternator?
 
Hi Krzysztof - this is precisely the reason I know the answer to your question.

I had had a power steering pump rebuilt by Jay Stratton (https://www.jaysbmwparts.com/) that I had sitting around for a year or so. I decided to install the rebuilt pump late last year. After Stan's alternator went kaput at Legends of the Autobahn in Hilton Head, SC (see here: https://e9coupe.com/forum/threads/legends-east-attendance.38951/post-337980), I determined to change to the later setup running the power steering pump off of the harmonic balancer instead of the water pump at the same time. I don't know that the original setup caused and/or contributed to Stan's problem, but because it seemed like this was a possibility, I decided to change. And, of course, BMW likely viewed this design as superior or they would not have bothered to make this change.

You need to change the pulley that mounts onto the harmonic balancer to a pulley with two grooves, and the power steering pump mounting bracket because you need to move the pump on a slightly different plane to tighten the belt. And, of course, you need the 900mm belt.
 
There are two pet numbers for the two groove pulley, 11 51 1 251 235 for all 2800CS and 11 51 1 255 356 for all 3.0CS until MY 74 which now had the single groove pulley, 11 51 1 251 234 in which the PS pump was driven by the crank. And at 1974 VINs 4310304 and 4335367 the fan clutch was now the viscous style.

No diameters are given in the parts book but the change was from 2800CS to 3.0CS.
 
Chris - I had originally used the 1075mm belt because I couldn't find another belt specified, but I had to swing the alternator all the way to the end of the bracket and the belt was barely tight enough. I changed to a Gates 9412 for an alternator belt 12mm x 1050mm.
 
On this same subject about different belt sizes and lengths I am having trouble with replacing the belt for the original AC system. The workshop manual says 13mm x 850mm. I have tried putting on this belt and it is way to wide to fit in the pullies properly. It rubs against the other belt on the crank pulley. I tried a 12.5mm x 875mm and again to wide and to short. I talked to Carl at La jolla and he said there are a lot of different sizes depending on the AC compressor and engine pulley setup. I measured the pulley groves on the AC compressor and engine . They seem to be around 11mm. I am going to try an 11mm x 875mm or even a 10mm. Has anyone else had this issue ? and what did you end up using.
 
I don't have an exact solution for you, but have been looking at belts (some on order) using the Gates website. There is black banner that allows you to specify a variety of parameters (picture below). You may need to order a couple from your local store to find the fit you are looking for.



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I’m using a 10mm Gates 7330 on ac pulley. The 12mm made noise. All good since. Agreed you may have to experiment with length.
 
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