Castor blocks question

SpeedyS2 · 09-03-2012, 02:02 PM

I replaced the castor blocks on my '90 S2 this morning (drivers side was old style, passenger newer - decided to replace both with updated 951 parts) and I have a quick question.

While removing the 19mm nut on the end of the eccentric through bolt, I noticed the eccentric did not move (turn) at all. Now, obviously the free end of the control arm would move when the castor block was removed, so I'm sure the alignment is off a bit now, but is it possible the alignment could be fine?

I'm taking the car for a track inspection in a few days and I'm planning to have them check the front alignment anyway, but I expected the eccentric to move and there to be more involved in the installation than simply unbolting the old block, slipping on the new one, and tightening things back up.

Do I not understand exactly (a likely scenario) how this works? Thanks for any input!

flash968 · 09-03-2012, 02:31 PM

it definitely should have moved the rear point of the control arm as you rotate it.

SpeedyS2 · 09-04-2012, 08:07 AM

Thinking about this some more, I guess the location of the nut at the back of the castor block simply adjusts the castor fore and aft. There's nothing more to it? What does the eccentric accomplish?

flash968 · 09-04-2012, 08:10 AM

caster is the adjustment of fore/aft. that is exactly what the eccentric does. as it rotates, it moves the control arm forward and backward.

unfortunately it also changes toe as it does that.

SpeedyS2 · 09-04-2012, 10:07 AM

Quote:

Originally Posted by flash968

caster is the adjustment of fore/aft. that is exactly what the eccentric does. as it rotates, it moves the control arm forward and backward.

unfortunately it also changes toe as it does that.

OK, thank you. So if the eccentric did not rotate at all, it is possible the alignment is very close to what is was before I installed the new blocks?

I'm still going to have it checked, though...

968 GUY · 968 GUY's Garage

The nut you removed was the securing or locking nut. It is possible for the eccentric to not move when removing the nut. More than likely, in fact, it is best to realign the car. Best to replace suspension parts when you plan to realign unless you have a good working relationship with a good shop that does not charge a lot.

flash968 · 09-04-2012, 06:58 PM

you can tell if it is in the same place by whether or not it pulls. caster is what makes the car go straight. if it now pulls, the block is not in the same place.

i just had the engine out of the car, and to do that i had to drop the caster blocks. try as we might to mark everything and get them right back in the same place, it didn't happen. the marks all lined up just fine, but still i was 2 tenths of a degree off, which made the car pull.

SpeedyS2 · 09-05-2012, 05:49 AM

Quote:

Originally Posted by flash968

you can tell if it is in the same place by whether or not it pulls. caster is what makes the car go straight. if it now pulls, the block is not in the same place.

i just had the engine out of the car, and to do that i had to drop the caster blocks. try as we might to mark everything and get them right back in the same place, it didn't happen. the marks all lined up just fine, but still i was 2 tenths of a degree off, which made the car pull.

Thanks to all.

The car does not seem to pull, but I'm sure things aren't exactly the same as they were.

I'm taking it in for a track inspection at a shop which is proficient at aligning 944's, and I'll have them check the front while it's there. Hopefully things aren't too far off and it's not a lot of work to get it back to spec.

44CUPMASTER · 09-13-2012, 06:50 AM

the adjustment part where the wrench gose on the caster adjuster should be facing down in the 4 or 5 o'clock position . that is very close to the correct spec without doing a four wheel .