W115 240D - squealing/difficult power steering at extremely low speeds

[j-galap]

Hi folks,

My 1974 240D has just developed a bit of a power steering problem!

When I'm parking, at extremely low speeds/stationary, the power steering has started squealing quite nicely! Also, there's been a couple of instances the last few days where the steering doesn't want to turn at all unless I'm moving a few mph faster.

I just checked the power steering fluid and it's full (although I don't know how old the fluid/filter is). I also replaced the power steering belt last summer so that's still fresh.

What would be my first port of call?

Thanks!

[Sugar Bear]

The belt has probably stretched and needs to be re-tensioned.

Replace the PS filter and fluid as maintenance. Flushing the PS system with fresh fluid while the return line is directed into a container is much better.

Good luck!!!

[cleeves]

Originally Posted by Sugar Bear

The belt has probably stretched and needs to be re-tensioned.

Replace the PS filter and fluid as maintenance. Flushing the PS system with fresh fluid while the return line is directed into a container is much better.

Good luck!!!

+1. Check PS belt and replace if its worn. It's probably very loose; in my experience it doesn't need to be as tight as the alternator and much less than the AC.

Good thing for you, the PS belt comes off first on a W115, or at least it does on a 300D.

-Henry

[j-galap]

Will do that, thank you!

What's the current recommended PS fluid to use? I've gathered I should avoid ATF!

Synpower power steering fluid?

[Idle]

Have someone turn the wheel while you watch the steering box. The bolts on the steering box have been known to break and this will give you a weird feeling depending on which three of the bolts break.

If the steering wheel is being turned and the steering box flexes at all then you have a broken bolt. The good part is this is about the easier fix there is as the bolts are easy to see and get to just behind the tire.

But I would lean towards the stretched belt theory myself. Don't use any 'belt dressing' on the belt as that stuff was formulated for drive belts used in the 30s. It is supposed to make your belts grip better but all it does is polish up the grooves in your pully wheels.

[j-galap]

All back together now.

During the work, I noticed that there appears to be a bolt missing here:



It certainly feels like there's a thread in there. Is that the locking bolt? Would explain why the belt came loose initially... and if so, does anyone know what size/thread/etc the bolt would be? It's a real pain to get to that hole!

Thanks

[cleeves]

Originally Posted by j-galap

All back together now.

During the work, I noticed that there appears to be a bolt missing here:



It certainly feels like there's a thread in there. Is that the locking bolt? Would explain why the belt came loose initially... and if so, does anyone know what size/thread/etc the bolt would be? It's a real pain to get to that hole!

Thanks

I think it is, and that story makes sense. It looks like an oblong slot, so loosening the bolt would allow lateral play in the pump. I don't know what size it is, but it's probably the same thread as the one on the other side. If it were me, I'd try to find it in the manual, and if that didn't work, take out the one on the other side, go to Lowe's, size it in their bolt dept, and buy a quality grade replacement on McMaster Carr in a few different overall lengths to try out.

-Henry

[801mbz]

make sure the bracket holding the pump isn't loose you are missing another bolt left of arrow see the small hole check that nut left of that hole. there should be one below also and one more going into oil pan near the rear adj bolt check the support bracket too

[j-galap]

Where do you mean? I had a look and couldn't see any missing bolt in that area

[Screwdriva]

I experienced this noise on my 76 240D. Here's what I did:

1) Auto -Rx additive in the existing fluid and drove 1000 miles as instructed.

2) Drained oil and then flushed with 2 bottles of Febi Bilstein power steering fluid with the car running before filling the reservoir with the 3rd bottle along with a new OE filter.

Noise totally gone. No leaks, squeaks or creaks.

[801mbz]

left of arrow nut that holds u shaped bracket that goes around crank pulleys that bolts to oil pan and other side of pulleys on block that u shaped bracket has a hole for 8mm bolt 13 mm head it bolts u bracket to ps bracket hole in u bracket could be bigger to ease alignment.call if I have confused you or need a bracket or other used part I may have. I have some parts cars that are going away soon.801 706 6871