retcav1sg

take a look and tell me what this is. Looks like a stamp of some kind. They are supposed to be the 16x7 and 16x8 7 slots that are original to my car. I'm removing the chrome ones that were on the car. The other pictures show the wheels to be in good condition.

gbarron

[/QUOTE]

That's where the RDK (tire pressure) sensors would go. RDK was first used in 1989 on 928's if I remember correctly.

I have not seen one like that before...is it cast into the wheel? Is there anything on the inside? Almost looks like a marking point for machining. There should be another one 180 degrees around the other side of the wheel.

What are the P/N's stamped into the wheels? Offset?

Rob Edwards

It's an RDK sensor that looks like it got painted over. For the US market that's a '90 or '91 wheel, 928 362 155 00/01 or 928 362 157 00/01

retcav1sg

So I guess the question is, did all cars come with the RDK system or was it just an option? If an option, I can see that as a stamp mark (my hope) for where the sensors would go for those cars so optioned. I guess either way, this shouldn't effect the performance of the wheels.

FredR

As I am aware RDK started with my late 90 S4 MY. For sure the 90S4 had them.

retcav1sg

Rob was correct, I zoomed in on one of the other pictures and sure enough, I can see the other side of one of the sensors through the slot. As I don't have RDK in my 88 S4, I guess I'll have wheels with useless sensors in them. Only concern is if they leak.

gbarron

I agree with Rob...it looks like the sensor got painted over. Best way to tell is look on the inside of the wheel, you should see the pick-up side of the sensor poking through. I think RDK was standard on all 928's in the years it was available.

gbarron

[QUOTE Only concern is if they leak.[/QUOTE]

Yep, and the tooling to R&I the sensors to change the leaking o-rings isn't cheap...

gbarron

My '89 ROW S4 has them from the factory. I think '89 was the first year for factory production RDK on the 928.

worf928