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So this happened to me tonight. The power steering pump pulley sheered off while driving in a straight line. Not a pleasant sound. There is not too much damage from the pulley and belt rattling around. The main coolant hose is danaged there may be more damage but it's hard to tell on the side of the road. The pump still spins smoothly though. Is the a rare or frequent failure?
Last edited by Michael Benno; 10-12-2016 at 07:46 PM.
The hollow dowel slips back into the pump and just the 3 bolts are left. I change the hardware to grade 10.9, use Loctite, and torque to 94 inch pounds.
The other thing that helps is remember to not hold these cats at lock, when making tight maneuvers. The turning resistance of the pump goes way up and keeping the pulley on can be a full time job. If you need to make a tight maneuver, turn the steering wheel to the lock and back off 1/4 of a turn.
There were posts from someone a few years ago who kept blowing out his steering rack seals. Turned out he had a difficult garage/driveway arrangement and held the wheel against the lock every time he went out.
I don't think there is anything in owners manuals about doing this, but most people treat machines with sensitivity - they can hear the pump screaming "Stop it!" at full lock. But some can't, or don't care.
You seem like a sensitive man, Michael. I'm just taking this opportunity to advocate for mechanical empathy.
The hollow dowel slips back into the pump and just the 3 bolts are left. I change the hardware to grade 10.9, use Loctite, and torque to 94 inch pounds.
The other thing that helps is remember to not hold these cats at lock, when making tight maneuvers. The turning resistance of the pump goes way up and keeping the pulley on can be a full time job. If you need to make a tight maneuver, turn the steering wheel to the lock and back off 1/4 of a turn.
Thanks Gregg, it's good to know that they are prone to failure. I was thinking something else caused the failure like belt too tight. I did have the belt replaced with the TB/WP project. I doubt the tension would be so high it would have caused the break without pump noise.
I guess buying a used pulley would be a bad idea. Is there a better pulley? or should I add a faceplate to the front of the pulley for added strength?
There were posts from someone a few years ago who kept blowing out his steering rack seals. Turned out he had a difficult garage/driveway arrangement and held the wheel against the lock every time he went out.
I don't think there is anything in owners manuals about doing this, but most people treat machines with sensitivity - they can hear the pump screaming "Stop it!" at full lock. But some can't, or don't care.
You seem like a sensitive man, Michael. I'm just taking this opportunity to advocate for mechanical empathy.
Might have been my post....
I had a client who I couldn't keep steering rack or pulleys on his car....every week one or the other failed. Was making me nuts....
I finally questioned him and found out he had just moved and getting into his new parking place required steering at lock....or an extra for and aft movement.
He added the extra movement. I "ate" several pulleys and steering rack rebuilds....
The hollow dowel slips back into the pump and just the 3 bolts are left. I change the hardware to grade 10.9, use Loctite, and torque to 94 inch pounds.
The other thing that helps is remember to not hold these cats at lock, when making tight maneuvers. The turning resistance of the pump goes way up and keeping the pulley on can be a full time job. If you need to make a tight maneuver, turn the steering wheel to the lock and back off 1/4 of a turn.
So, I'm replacing my PS pump and need to migrate the pulley over. The PS pump pulley torque is 94 in-lbs with locktite blue then? Is there a particular tool required to remove the pulley from the old pump?
So, I'm replacing my PS pump and need to migrate the pulley over. The PS pump pulley torque is 94 in-lbs with locktite blue then? Is there a particular tool required to remove the pulley from the old pump?
72 in-lbs with the original hardware. Blue Loctite will not hurt, as long as you keep it from getting between the pump and the pulley.
Out of curiosity, could replacing the high pressure hose with a non-restricted pipe cause this type of failure?
Not sure how lowering the pressure would cause the pulley to break. You would have to explain your theory a little bit more....
In my case, the pulley failure was the result of one of the three mounting bolts heads failing. This could have been the result of over tension from the recent belt change, or it could have been a result of one of the three bolts coming loose, or a result of the metal failing in the pulley itself.
Another possible failure could be the design itself is flawed. Gregg points out that this failure does seem to happen with some frequency. I noticed the original pulley was mounted with bolts without washers. The replacement pulley had bolts with washers included. So maybe the added surface area of the washers offers better mounting.
Not sure how lowering the pressure would cause the pulley to break. You would have to explain your theory a little bit more....
When I replaced my hose I read a lot about the reason for Porsche putting a restrictor in the line and one of the theories was to limit the load on the pump when the wheel is turned quickly or on the end stop, so just wondering if replacement of the hose coincided with an increased chance of failure.
No, the maximum pressure is limited by the relief cartridge which is in the pump itself. This is what limits the amount of torque that the pump can take.
10-12-2016, 01:22 AM
Power steering pump pulley failure
