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Replacing front suspension bushes

Posted: Fri Sep 13, 2013 9:54 am
by Boris64
Hi,

Further to my earlier link about tyre wear (thanks for the advice) I now propose to replace the front end suspension bushes ahead of adjusting camber and sorting out the tracking.

I have bought a full front end polybush set from ESM plus 2 rubber bushes (1 each) for the tie bars.

With apologies for using someone else's photo - terrific for the job.

In this image is everything free from load/tension and in this state will I be able to remove all nuts and bolts without any surprises?

Is the torsion bar still under load?

Thanks

Pete[frame]Image[/frame]

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 11:10 am
by MarkyB
NO!
In that picture it's still under tension and resting on the bottom stop.
It needs to be jacked up under the end of the cast iron half of the suspension arm untill it comes off the stop.
Then the pressed part of the arm is unbolted including the nut on the trunnion pin.
This will allow the suspension leg to be disconnected from the cast iron part.
Then the jack can be let down and the tension will be out of the torsion bar.

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 11:28 am
by mike.perry
You will probably find that setting the tracking will solve your tyre wear
The chassis must be supported on axle stands and the torsion bar must be supported by a jack under the end if the lower suspension arm whist the swivel pin is removed. The jack can then be lowered to take the load off the torsion bar.

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 12:08 pm
by Boris64
MarkyB, Mike,

Many thanks for quick replies.

All makes sense thanks.

I hadn't picked up that the rear arm was cast.

Will I be able to do everything without disengaging the torsion bar?

White grease on bushes?

Thanks

Pete

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 6:16 pm
by MarkyB
Will I be able to do everything without disengaging the torsion bar
You cant replace the rear eyebolt bush with the torsion bar in place.
I've never had much luck marking the torsion bar and arm so they go back in the same place, you can give it a go.
Better to measure how far from the ground the end of the arm is before you take it off then replicate when you put it back.

You don't need to disconnect the track rod end as shown in the picture either.

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 7:37 pm
by bmcecosse
It has to be disengaged - but that is very simple to do..... Well done getting two rubber bushes for the tie bars - they go on the inside - poly on the outside.

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 8:22 pm
by philthehill
You can if you are careful knock the cast suspension arm rearwards on the torsion bar front splines enough to disengage the eye bolt and eye pin without driving it completely off the front torsion bar splines and so retaining your suspension height setting. If the eye pin cup washer which fits inside the front of the cast suspension arm is seized continue knocking the cast arm rearwards because the eye bolt pin will eventually come up against the front of the torsion car and it cannot go any further. With further careful hammering to the cast arm the eye bolt and cup washer will disengage from the cast arm. Undo and remove the eyebolt retaining nut, twist the eye bolt and it will come free enough to remove and then you can replace the bushes.
If you can use a copper hammer when knocking the arm you are less likely to damage the arm when hammering.
A good soak with release oil before dismantling will help the job along nicely.
When you have got the suspension arm disengaged from the swivel and sitting neutral it is a good idea to measure and record the height. I always use a strip of ply placed vertically (and against the arm) bottom on the ground and just long enough to reach above the outer end of the cast suspension arm; then by putting a marker pen through the trunnion pin hole it marks the plywood so giving you your datum point. Unless you change the height of the chassis leg you can easily use the marked ply (datum point) to reset the suspension arm. I always make sure that I mark the ply TOP and BOTTOM!!!!!!!!!!!

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 9:27 pm
by bmcecosse
I just use whatever spanner is lying there -and use it as a height gauge...

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 9:55 pm
by ColinChandler
As Phil says, I've always been able to just (gently) knock the cast arm back far enough to clear the chassis eyebolt without it coming off the splines. You might be lucky to get away with it too but just in case, measure or make a template first. :)
After the event is too late.
Good luck, Colin.

Re: Replacing front suspension bushes

Posted: Fri Sep 13, 2013 10:58 pm
by mike.perry
Mark the torsion bar/ lower arm with tipex or similar
Replace the eye bolt bushes with metalastik bushes.

Re: Replacing front suspension bushes

Posted: Sat Sep 14, 2013 9:43 am
by Boris64
Gents,

Many thanks for the prompt and clear advice.

I will attempt to join those who have succeeded in knocking the suspension arm backwards to release the eyebolt bushes - fingers crossed.

I'll measure anyway for record and assume this is use once and throw away as its dependant on the height of the axle stands ?

Too late for metalastic bushes, I have the poly kit, but thanks for the tip.

I was able to get both wheels off early this morning before the junior mechanic took Boris and have cleaned and oiled everything for what I hope will be bit of fun at some stage this weekend.

Bmc - the two rubber bushes are for the 1275 crankcase vent :wink:

Pete

Re: Replacing front suspension bushes

Posted: Sat Sep 14, 2013 10:31 am
by chickenjohn
MarkyB wrote:NO!
In that picture it's still under tension and resting on the bottom stop.
It needs to be jacked up under the end of the cast iron half of the suspension arm untill it comes off the stop.
Then the pressed part of the arm is unbolted including the nut on the trunnion pin.
This will allow the suspension leg to be disconnected from the cast iron part.
Then the jack can be let down and the tension will be out of the torsion bar.
As Marky said, unbolt and remove the front half of the two piece wishbone, then jack the rear half of the wishbone to relieve the tension, the nut can then be undone and the lower trunnion pulled out of the rear half of the wishbone.

As I often say, it make the job FAR easier if you have a decent set of Whitworth spanners and sockets as all (most) of the suspension nuts and bolts will be WHitworth heads with a BSF thread.

Re: Replacing front suspension bushes

Posted: Sat Sep 14, 2013 11:10 am
by bmcecosse
Pete - you've lost me - rubber bushes for 1275 vent????? At the tiebar front mount - you want a rubber bush on the inside and a poly bush on the outside...two poly bushes here are TOO TIGHT and (as well as being v difficult to tighten) leave no resilience.

Re: Replacing front suspension bushes

Posted: Sat Sep 14, 2013 6:06 pm
by Boris64
Bmc,

a lame joke on my part that fell on stony ground :(

I'm clear on both counts from your earlier posts, unless maybe they would protect the coil from inevitable failure :wink:

Pete

Re: Replacing front suspension bushes

Posted: Sat Sep 14, 2013 7:35 pm
by bmcecosse
Hohoho -I think :( :lol:

Re: Replacing front suspension bushes

Posted: Tue Sep 17, 2013 5:46 pm
by Boris64
:D

Thanks to all for advice on this subject.

I've done the offside bushes and posted the details in the restoration thread to keep Boris' story in one place.

Pete