M coupe steering rack ded

[Lure]

Well my steering rack went out...major vibration in the wheels. I thought it was fcab or tie rods but nope! Anyone had one rebuilt by rackdoctors?

[Jsinghzzzz]

https://www.zpost.com/forums/showthread.php?t=1563265

RackDoctor recommendation per KevinC

Looks like it worked out well thus far for RDMZ4M

[Michael9218]

Are you sure it's the rack and not the pump?
Is your rack leaking?
My experience has been when the wheel throbs its typically because the pump can't hold pressure. If it's the rack blowing a seal, you should see fluid leaking badly.

Rack Doctor just serviced my M Coupe rack. Great company.

[longress]

Following.... I've never heard of a failed steering rack causing a vibration.

[Lure]

Hmm could be the pump also...but the rack has definitely some excessive play in the driver side. Gonna send the rack out to rackdoctors anyway. I spoke to them on the phone and wow what a nice thing to speak to the actual owners on the phone!

[Michael9218]

Originally Posted by Lure

Hmm could be the pump also...but the rack has definitely some excessive play in the driver side. Gonna send the rack out to rackdoctors anyway. I spoke to them on the phone and wow what a nice thing to speak to the actual owners on the phone!

Let us know what he finds. Excess play sounds like an inner or outer ball joint.
Can you feel play in the tie rod?

Rich is a great guy. Very helpful and happens to be a BMW enthusiast.

[Lure]

[IMG][/IMG] dealing rackdoctor was a very nice experience! Very fast and helpful. I have to check a few things on install I was having pulse and shaking when the car was at a stop. So possible cavitation from cracked pump reservoir also.

[lapoune]

I'm curious, for one of you with a rack out of the car, can someone measure the movement of the rack per revolution, or lock-to-lock with the tie-rods on?

Recently bought a remanufactured rack from BMW, and I'm not sure I received the right part...

[Michael9218]

Coupe and Roadster have different racks. Which one are wanting to compare to?
IIRC, Roadster is 3 turns lock to lock. Coupe is 2.7.

[lapoune]

I know, but I'm looking for a hands on confirmation of the differences between the 2 racks.

My BMW reman'd coupe rack for example measured at 50mm\rev and 2.7 turns lock to lock, which doesn't match what people report on the internet, it more closely matches the roadster rack reported numbers. I've seen reports of 54mm\rev (translates to about 2.5 turns lock to lock) for coupe racks, but I'm starting to doubt these numbers.

Lots of misinformation around these things so would be cool to clarify some of this while some people conveniently have their racks out!