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Author Topic: Sierra front arb double washer mod  (Read 474 times)

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Offline scud

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Sierra front arb double washer mod
« on: February 17, 2020, 13:29:15 PM »
I remember years back seeing Tony saying that you can double up the rear washers on the arb to tca Bush(void Bush) and that it would affect the geometry in such a way that understands is reduced.
Has anyone tried it?  Did it work?

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Offline Marc

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Re: Sierra front arb double washer mod
« Reply #1 on: March 10, 2020, 12:33:58 PM »
Adding the washers there increases caster of the front wheels. That does give some additional front camber when the steering wheel is turned, so it could reduce a bit of understeer. Additional caster will also help with straight line stability.

Be aware that after the washers are added you will need to have the tracking done, as the washers will also change the toe setting.


'90 Sapphire Cosworth 4x4
'91 Sapphire 2.9 24v RWD

Offline scud

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Re: Sierra front arb double washer mod
« Reply #2 on: March 15, 2020, 15:46:19 PM »
thanks Marc I knew it would change the castor but hadn't realised the camber would also be affected so im going to give it a trial since I was replacing the tca's and reinstalling the rack anyhow and ive had a set of spare washers since I read tonys comments about it years back  :2tu:

Offline scud

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Re: Sierra front arb double washer mod
« Reply #3 on: March 29, 2020, 14:04:01 PM »
I don't recommend this.
it was worth a try, turn in felt improved and steering was lighter but it came with fairly bad instability and shuddering steering wheel under heavy braking and a lot of bump steer, minimal for normal driving but still a little unpredictable

Offline Marc

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Re: Sierra front arb double washer mod
« Reply #4 on: March 30, 2020, 19:34:08 PM »
I don’t understand any of the things you mention. Basically you are just increasing the caster, nothing more. Did you have the front toe setting checked/adjusted afterwards?

The change in bump steer should be completely unnoticeable.


'90 Sapphire Cosworth 4x4
'91 Sapphire 2.9 24v RWD

Offline scud

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Re: Sierra front arb double washer mod
« Reply #5 on: March 30, 2020, 19:51:50 PM »
Yes the toe was set correctly, you said earlier it should affect the camber too but the Caster change totally ruined things, as soon as I changed it back it was fine,  even without getting the toe reset

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Offline scud

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Re: Sierra front arb double washer mod
« Reply #6 on: March 30, 2020, 19:53:12 PM »
At least  I know  now it was an interesting experience

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Offline Marc

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Re: Sierra front arb double washer mod
« Reply #7 on: March 31, 2020, 13:30:37 PM »
Very strange. I ran my car for years with a washer between the ARB and tca to increase the caster, it didn’t give any problems at all.

Did you get the print out with all the alignment angles?


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Re: Sierra front arb double washer mod
« Reply #8 on: April 10, 2020, 18:59:25 PM »
yes it surprised me that is made so much difference especially the turn in being apparently improved.
I think the toe was 2 mm toe in

 

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