Couple of L300 front end questions.

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uted
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Couple of L300 front end questions.

Post by uted »

It's been suggested to me that my project with L300 needs some more caster. Apart from placing a shim at the cross member / chassis bracket is there another method ? Anybody here with an L300, can you measure the gap at the lower bumpstop rubber please.
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FRANK BASILE
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Re: Couple of L300 front end questions.

Post by FRANK BASILE »

What was the reason given for "needing more castor?" They will already have a factory spec. Trying to remember back with my dabbling when I fitted mounting brackets to suit a chassis,the aim was to have the crossmember parallel to the ground at ride height, castor adjusment was by shims on the upper control arms,and you have castor bars on the lower arms .
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zuffen
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Re: Couple of L300 front end questions.

Post by zuffen »

Frank,

Maybe a correction.

Camber, not Caster, is adjustable by shims on top arm and caster bars on lower arms look after caster.
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uted
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Re: Couple of L300 front end questions.

Post by uted »

When coming out of a corner the steering wheel does not self centre very much.
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46 deluxe
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Re: Couple of L300 front end questions.

Post by 46 deluxe »

Needs more caster then , that will help to pull steering back to center .
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zuffen
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Re: Couple of L300 front end questions.

Post by zuffen »

Bear in mind the more Caster you have the steering will become a little more responsive and lighter plus vehicle may feel more twitchy if taken too far.

Caster can also be affected by the rake of the chassis, so even changing ride height or tyre size (front or rear) can alter Caster.
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Re: Couple of L300 front end questions.

Post by 46 deluxe »

Depends on the caster setting Zuffen .
Negative caster will make steering light and twitchy .
Positive caster will make steering heavier and more stable .
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Re: Couple of L300 front end questions.

Post by zuffen »

From Uted description it has too much positive caster.

Best move would be to have it aligned so they can tell you exactly what settings the vehicle is at so you can then make informed decisions on correcting the problem.
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Re: Couple of L300 front end questions.

Post by uted »

Toe in probably has something to do with it also. Valid point on the chassis rake.
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Re: Couple of L300 front end questions.

Post by Sudsy »

You can adjust camber and caster with the shims at the top. To increase caster add shims to the front mounting bolt on the top arm only. I always set them up to have between 5 and 7 degrees of caster and they steer great.
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Re: Couple of L300 front end questions.

Post by uted »

Thanks Bob. 8)
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Re: Couple of L300 front end questions.

Post by uted »

Just another question on the strut rods. They have a threaded section with bushes and adjustable nuts. I can't find anywhere the process for adjusting these rods. Can someone help me with that please.
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Re: Couple of L300 front end questions.

Post by FRANK BASILE »

Those "Castor Bars" will only give limited adjustment or fine tuning. Look at the design where the lower control arms are held by a narrow bush on the pivot bolt. Those bars limit for/aft movement of that lower arm once the bushes are compressed by the retaining nuts/washers. The inner bush is not ideally cocked to an angle. The castor and camber is ideally adjusted via the top control arm shims. Different thickness front/rear on the upper pivot bar does this. Early Mustang/Falcon design is similar principle. Holden style front ends do not use "Castor" rods as the lower arms are "VEE" shaped with front rear bush pivots making any movement for/aft impossible unless the bushes are chewed out. Castor /camber is adjusted as per the L300 upper arm shims on the pivot bar. To answer the question on adjustment procedure for the struts. I would adjust them tight to keeping the lower control arm as straight as possible parallel. Thinking about it to explain . With no rod attached and no lower ball joint attached, swing the arm up and down and with the bush bolt tightened you will have firm up down movement, now pull the arm forward or aft and do the same up down,it will be felt tighter due to forcing angular strain on the bush. This abnormality will also occur if those strut bushes are adjusted to either extremity. Hope this helps
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Re: Couple of L300 front end questions.

Post by turns »

I suggest that you measure (as accurately as possible) where everything sits currently and go from there. Time will be the largest investment.

I do it on the workshop floor using fairly rudimentary techniques ie angle finder, tape measure, string lines, plumb bob etc. Even then I still go and get a wheel alignment. I have a local place that accepts and knows I want to stand next to the guy and discuss the process.

The effort put into tuning a chassis (suspension/steering etc) makes a huge difference in how the vehicle will drive.

Just my thoughts

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uted
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Re: Couple of L300 front end questions.

Post by uted »

Thanks to both of you -- that pretty much explains it all.
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