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live axle alignment....? help!
foes - 28/4/08 at 09:59 PM

Right, im building (well nearly built!) a live axle'd r1 powered locost (stuart taylor chassis) its still on axle stands and i bolted my wheels on for the first time today and it looks like the axle is sitting off to the near side....? if i measure from the rim to the trailing arm in the same place on both sides the gap on the off side is approx 4-5mm smaller than the gap on the near side. The chassis and axle were both supplied (well i provided the axle and ian gray had it modified) by stuart taylor.... It looks to me like the brackets haven't been put on in the correct place ie. central...? Any help appreciated and please don't say a strip down and bracktets re-welded on

carl.


daviep - 28/4/08 at 10:03 PM

Panhard rod length correct? How does the axle sit without the panhard rod fitted?


MikeR - 28/4/08 at 10:08 PM

to make absolutely sure, measure from one side of the axle to the other. Use that to mark the centre of the axle, then check from the centre of the axle to the mountings measurement.

I haven't double checked but i think the mountings should be identical - but measuring from the centreline should confirm if its an issue or not.


foes - 28/4/08 at 10:28 PM

quote:
Originally posted by daviep
Panhard rod length correct? How does the axle sit without the panhard rod fitted?


Panhard rod not fitted yet...


blakep82 - 28/4/08 at 11:01 PM

quote:
Originally posted by foes
quote:
Originally posted by daviep
Panhard rod length correct? How does the axle sit without the panhard rod fitted?


Panhard rod not fitted yet...


put that on and check again. without the panhard rod, the axle is free to move side to side quite a bit.

check the measurements of the centralility (good new word...) of the brackets too though.


foes - 28/4/08 at 11:21 PM

quote:


put that on and check again. without the panhard rod, the axle is free to move side to side quite a bit.

check the measurements of the centralility (good new word...) of the brackets too though.


centralility, like it.... thing is my panhard rod is adjustable (?) in length, but shouldn't the axle sit central in the first place and the panhard rod just hold it there? or can it be used as a way of setting the axle central..?
carl.


blakep82 - 28/4/08 at 11:31 PM

well... yeah, i guess idelally it should be central naturally. i wouldn't say 4mm is a huge amout out (if its showing 4mm more on one side than the other, its only actually 2mm, i think... yeah, eg, 21mm one side, 25mm on the other... take 2mm off 25, and add to 21, you've got 23 and 23)

adjust your panhard rod to set the axle central. the panhard rod is there to stop things moving side to side.

for example, my axle is mounted with rose joints, without a panhard rod (well, watts link in my case) my axle's free to move side to side until the wheel hits the chassis, about 12" in total. i gather you're using bushes though, so they won't allow as much side to side movement, but use the adjustment in the panhard rod for fine adjustment.

depending on your set up, i think a few things can affect the way it hangs natually, but the panhard rod will hold things. remember, that with a panhard rod, when the axle moves up and down in moves in an arc, you may find if you set it centrally now, once you lower the car to the ground it'll be out again... its just the way they work.



[Edited on 28/4/08 by blakep82]


foes - 28/4/08 at 11:41 PM

Just done a couple of quick measurements on the axle...
I measured from the inner face of the outboard axle flange (what the backplate and bearing retainers bolts to) to the inboard side of the trailing arm bracket, on both sides of the axle.
offside measurement = 100mm
nearside measurement = 104mm
i assume this means the brackets are not located centrally on the axle then?
any ideas what i can do about this? and what effect it would have on handling?


foes - 28/4/08 at 11:49 PM

blakep82, after i had posted i was just thinking the exact same thing if rose joints had been used instead of bushes

So if i get all four wheels on, get the car on the ground and try set the axle central with the panhard rod it should ok....?

yeh true if its 4mm out, it only needs to be moved 2mm to get it central...


blakep82 - 29/4/08 at 12:01 AM

2mm isn't a huge amount. well, tiny in fact. lol, i've only judged mine by eye
i've got rose joints all round on mine so i've got loads of adjustment, but yeah, i wouldn't worry about 4mm (or 2mm really) too much

like i was saying though, if its a panhard rod you've got its going to move in a side to side arc anyway, i don't know by how much, but i'd say by more that 4mm anyway.


foes - 29/4/08 at 12:09 AM

quote:
Originally posted by blakep82
2mm isn't a huge amount. well, tiny in fact. lol, i've only judged mine by eye
i've got rose joints all round on mine so i've got loads of adjustment, but yeah, i wouldn't worry about 4mm (or 2mm really) too much

like i was saying though, if its a panhard rod you've got its going to move in a side to side arc anyway, i don't know by how much, but i'd say by more that 4mm anyway.


well thats put my mind at rest thanks


C10CoryM - 29/4/08 at 02:42 AM

The panhard bar is all the holds the axle centered. It is the lateral locating device, not the bushings. Adjust it until your axle is bang on center at ride height. The bar should ideally be level at ride height. This keeps the sideways movement from the arc to a minimum.

FYI a 97cm long panhard bar will arc in about 3mm at 8cm of bump. Not enough to be noticable in virtually any car and rarely worth messing around with a watts link IMO. Watts link actually move in a slight S shape too .
Cheers.
Cory


Ivan - 29/4/08 at 06:36 AM

Aren't your brackets wider than the joints - in which case you can always shim out the difference.


David Jenkins - 29/4/08 at 07:48 AM

Just don't measure from the propshaft flange - that is off-center, by design!

[Edited on 29/4/08 by David Jenkins]


foes - 29/4/08 at 08:40 AM

quote:
Originally posted by David Jenkins
Just don't measure from the propshaft flange - that is off-center, by design!

[Edited on 29/4/08 by David Jenkins]


yes i know that, by a fair amount as well....


David Jenkins - 29/4/08 at 08:50 AM