Couple of L300 front end questions.
- uted
- Member
- Posts: 534
- Joined: Mon Mar 15, 2010 10:32 am
- Location: Perth WA Sandgroper country
Couple of L300 front end questions.
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.
"When better automobiles are built, Buick will build them"
- FRANK BASILE
- Old Hand
- Posts: 13902
- Joined: Wed May 07, 2003 3:14 pm
Re: Couple of L300 front end questions.
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 .
OZ-E-Rodders Rod and Kustom Club Member #31
- zuffen
- Old Hand
- Posts: 2034
- Joined: Fri Jan 28, 2011 7:45 pm
- Location: Sydney
Re: Couple of L300 front end questions.
Frank,
Maybe a correction.
Camber, not Caster, is adjustable by shims on top arm and caster bars on lower arms look after caster.
Maybe a correction.
Camber, not Caster, is adjustable by shims on top arm and caster bars on lower arms look after caster.
Never argue with an idiot, they will drag you down to their level and beat you with experience.
- uted
- Member
- Posts: 534
- Joined: Mon Mar 15, 2010 10:32 am
- Location: Perth WA Sandgroper country
Re: Couple of L300 front end questions.
When coming out of a corner the steering wheel does not self centre very much.
"When better automobiles are built, Buick will build them"
- 46 deluxe
- Old Hand
- Posts: 3656
- Joined: Sun Aug 17, 2003 12:50 am
- Location: geelong vic
Re: Couple of L300 front end questions.
Needs more caster then , that will help to pull steering back to center .
scott
- zuffen
- Old Hand
- Posts: 2034
- Joined: Fri Jan 28, 2011 7:45 pm
- Location: Sydney
Re: Couple of L300 front end questions.
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.
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.
Never argue with an idiot, they will drag you down to their level and beat you with experience.
- 46 deluxe
- Old Hand
- Posts: 3656
- Joined: Sun Aug 17, 2003 12:50 am
- Location: geelong vic
Re: Couple of L300 front end questions.
Depends on the caster setting Zuffen .
Negative caster will make steering light and twitchy .
Positive caster will make steering heavier and more stable .
Negative caster will make steering light and twitchy .
Positive caster will make steering heavier and more stable .
scott
- zuffen
- Old Hand
- Posts: 2034
- Joined: Fri Jan 28, 2011 7:45 pm
- Location: Sydney
Re: Couple of L300 front end questions.
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.
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.
Never argue with an idiot, they will drag you down to their level and beat you with experience.
- uted
- Member
- Posts: 534
- Joined: Mon Mar 15, 2010 10:32 am
- Location: Perth WA Sandgroper country
Re: Couple of L300 front end questions.
Toe in probably has something to do with it also. Valid point on the chassis rake.
"When better automobiles are built, Buick will build them"
- Sudsy
- Senior Member
- Posts: 1583
- Joined: Sat Apr 08, 2006 2:59 pm
- Location: Lower Mid North South Australia
Re: Couple of L300 front end questions.
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.
Regards Bob
- uted
- Member
- Posts: 534
- Joined: Mon Mar 15, 2010 10:32 am
- Location: Perth WA Sandgroper country
Re: Couple of L300 front end questions.
Thanks Bob.
"When better automobiles are built, Buick will build them"
- uted
- Member
- Posts: 534
- Joined: Mon Mar 15, 2010 10:32 am
- Location: Perth WA Sandgroper country
Re: Couple of L300 front end questions.
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.
"When better automobiles are built, Buick will build them"
- FRANK BASILE
- Old Hand
- Posts: 13902
- Joined: Wed May 07, 2003 3:14 pm
Re: Couple of L300 front end questions.
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
OZ-E-Rodders Rod and Kustom Club Member #31
- turns
- Old Hand
- Posts: 2925
- Joined: Mon Dec 17, 2007 8:23 pm
- Location: Sydney NSW
Re: Couple of L300 front end questions.
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
Cheers Turns
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
Cheers Turns
"Normal is an illusion. What is normal for the spider is chaos for the fly"...............Morticia Addams
- uted
- Member
- Posts: 534
- Joined: Mon Mar 15, 2010 10:32 am
- Location: Perth WA Sandgroper country
Re: Couple of L300 front end questions.
Thanks to both of you -- that pretty much explains it all.
"When better automobiles are built, Buick will build them"