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So this Easter I'm going to attempt to replace the ARB bushes.  I have a set of purple poly bushes from SJ, the front of the car is up in the air, wheels off ready to go. 

 

I've hunted through the forum and so far I can't find a torque specified for the nut on the ARB... is it just 'kin tight?

 

And, do you all think that I have to set ride height when doing it up?  Doing that will make it pretty hard to achieve without a hoist.  Is it critical for these bushes to be done at correct ride height, considering I'm only affecting the ARB bushes, and none of the other suspension bushes?

 

And just checking, in the manual it says 150mm and 170mm at front and rear of chassis box section.  That means I'm aiming for 150mm from the front of the box section to the ground, and 170mm from the rear of the box section to the ground?  With different tyres from when it was new (different sidewall strength), unknown tread wear etc etc!

 

Cheers,

Simon

 

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The nut does up on to a shoulder on the anti roll bar...so, yes, just 'kin tight!! Make sure the washer is the right way round. Also the car has to be at ride height.. I set mine with the vertical chassis member to which the A/R bar attaches at 170mm to the ground. The bushes have a marked affect on the ride height...first time I changed them it got rid of the RH front sag!! Sadly, I can't remember how I did it.... (!)

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Interesting question.

 

The manual states 6-10 lb/ft for the ARB to lower link, ie virtually nothing.

 

I am not sure about this though. I am assuming they are relying on the nyloc nut to stop it unwinding and the intention is to nip it up against the bushes without over-compressing them. I have to say I ignored that and tightened it fully up onto the shoulder on the ARB. The bushes didnt get over-compressed.

 

I would suggest give SJ a quick ring to check what they do.

 

These dont need to be tightened at ride height.

 

Not sure where you are getting the 150mm from, it should be 170mm. 

 

I found that if the ARB is powder-coated it creaks like an old bedstead when you go over a speed bump unless you lubricate the D-shaped bushes which mount it to the chassis with silicone grease. The bar rotates in those bushes.

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The 150 and 175mm figures are out of the service manual, page 6, CB.5. - Front Suspension Dissasembly, in the front suspension section.  Where are the torque figures you quoted?  I couldn't find any!

 

I'd have thought that the ride height bit is relatively unnecessary for the ARB, as it pivots against the chassis anyway for up/down suspension movement.  I find it hard to believe that clamping force (especially with the torque figures you've quoted) would affect the movement of ARB relative to lower link.  I'd guess that the torque figures are important with the older rubber style bushes to make sure they aren't deformed massively, and with poly it won't matter.  That being said I'll get it as close as I can to correct ride height anyway. 

 

I'm keen to sort the driver's side sag in this process so John I hope I do the same as you!

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In my manual they are on page TD D 8

 

Although I dont think any 2 of these manuals are the same! Just like the cars really :)

 

The table also tells which bolts should be torqued at ride height which are upper wishbones and lower link to chassis and the shock to lower link.

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Thanks Andy

So the ARB to lower link doesn't need to be done at ride height according to your manual. 

This is turning into a Lotus saga... the nut won't come off!  I spent most of the day on it today, I'll get a little cutting wheel for my dremel and try to cut the nut.  It's so round now that's my next option!

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I can see how that would happen as you cant get a ring spanner onto it. Sounds like a challenge!

 

Yes the manual has an asterisk in the torque list for nuts which need to be tightened at ride height and thats not one of them. The ARB rotates in the D-Bushes and the ones on the lower links simply compress and dont have any inner metal bush as the wishbone bushes have so there is nothing which needs to be set in any correct position.

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Well the bloody thing is off.  Rounded to hell and back, finally split it.  From the look of the threads there was some sort of threadlock material on it.  As well as being nyloc... in that position a recipe for disaster.  I hope the other side isn't as stupid. 

 

So the new bushes are on the drivers side, and I'm waiting now for the shops to open to replace the nut.  The book says it is M12 nyloc.  However, when I try a spare m12 nut, it's very hard to turn.  This is partly due to the remains of the threadlock (I gave it a good wire brush but there are some bits left).  When I take the m12 nut off again, the peaks of the thread seem damaged... no change to the ARB so I'm not cross threaded... I can keep going until there is thread coming out the other side of the nut, but it just gets tighter and tighter. 

 

Is there any chance it's not m12?  There's no reference to any other nut size in the book I have!

 

In reference to the advice about not removing the chassis brackets for the ARB in case I loose the alignment of the plate with nuts that the bolts go into... my chassis bracket bolts for the ARB seem to go straight into some structural tubes... with no apparent chance for there to be plates with nuts on?  The book shows this too.  This may be an early S3 thing?

 

Also, the washer isn't well suited to the new bushes, as the hole is too big.  The outside diameter is fine, but it doesn't locate well onto the threaded portion of the ARB.  I don't think I'd have any chance of getting the bushes compressed enough for the nut to sit against the shoulder at the end of the thread.  I think that's what needs to happen though?  That would see the washer sit on the larger diameter part, and seat correctly...

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The parts list shows the nut as M12 but it could be M12 fine.

 

On cars, M10 and M12 threads are often fine thread.

 

Other than that, its possible it is a 1/2in thread. To check this you could remove the shock mount nut which is 1/2 in UNF and try it on the ARB. 

 

On mine the D bush mountings are threaded straight into the chassis also.

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Got my arb in the shed...give me 1/2 hour and I'll measure up the thread for you.

I also have the same D bush mountings, straight into the subframe. Only thing to watch out for is keeping the shims in the right place ( mine was packed 2 one side, one the other. IIRC this is a camber adjustment?

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The shims are castor adjustment. Theoretically this needs to be checked anyway if the bushes are replaced. I havent yet though.

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Thanks all,

Thread doesn't look fine, looks normal to me.  I'll see if I can borrow a M12 die and clean the threads properly.  Part of the load on the nut is compressing the new bush of course...

 

My book also says the shims are castor adjustment (by pulling the lower arm forward or back I guess). 

I didn't have to take the D brackets off, just loosen them a bit.  Have you noticed any adverse behaviour since you changed yours? 

 

From memory castor is all about the 'return to straight ahead' force if you let go of the wheel, can anyone confirm if it's a major issue if it's not checked?

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Ok Simon, thread measures up as M12 x 1.75.

Think it's the standard thread rather than fine. I ran a plated m12 nut onto the bar end and it was very tight, so I guess the arb is just cut to top tolerance, threads matched up perfectly to the new bolt for pitch.

Are you not changing the D bushes?

I'll be interested to know how you get on with the SJ bushes too. Good luck,

Dave

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Thanks Dave

 

I had some great summers in Bude as a kid... nice spot to live.

 

I don't plan to change the D bushes, they look great.  The ARB bushes were awful so were on the list early on, then when I read about Molemot correcting the 'lean to the driver's side' issue with the replacement bushes it was definitely on. 

 

My car isn't too bad in terms of PO maintenance, there are some clear issues like the ARB bushes but you often find bits that are in very good nick. 

 

Thanks for your help, I'll let you know if there are any issues with the bushes.

Cheers,

Simon

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If you're working on your own, I found a ratchet strap really useful for pulling in the ends of the arb when I took it off.

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Another vote for a ratchet strap....I ended up using a Spanish WIndlass in the end, couldn't find the trailer straps!! This is one of those jobs that seem impossible until you have done them....and just as impossible the next time, too....

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I have a 'come along' winch (see comalongwinch.net for an image) standing by, but haven't needed it yet.  One side is done, waiting to get hold of a M12 nyloc tomorrow (I'll replace both nuts, the other side looks better but haven't got to try to undo it yet).

I used spring compressors and took the whole vertical link out, I don't know if that's how it's usually done.  With the D brackets loosened I was able to persuade the ARB out of the lower link, and back in again relatively easily. 

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Think I perefer the sound of a comealongwench :-).

BTW, loving Bude, only moved here a year ago, but I guess you've got it a bit better where you are now! Nice to know you have fond memories though.

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Sorry....can't resist it....

 

There was a young lady from Bude

Who danced on the stage in the nude

'Till one night, out front

Someone upped and yelled "****!"

Just like that...right out loud...bloody rude...!

 

(Grabs coat...exeunt stage left....)

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A little late, but an update:

 

All done, the second side was a walk in the park compared to the first.  Same amount of WD 40 applied, and the nut came off fine.

 

After fitting (I used new stainless steel nyloc nuts) I had another bout of ignition gremlins which I've cured (see post in engine forum about intermittent ignition fail), so I couldn't test to see what sort of improvement there was... but now I've done that.  

 

Ride height is still a little high, even though it was done up at the correct height... actually 170mm is fine by me, gets me over the dirt driveway a lot better and doesn't look 'up at the front' at all.  

 

Car does feel more positive through the turns, and turn in is improved.  Still leans a little to the left, but nowhere nearly as bad.  

Apart from the one nut that caused problems, it was an OK job to do, fairly obvious as to what needs doing next.  Another vote for trailer tie downs, the wide webbing grips the ends of the bar well.  

 

And, I discovered what the hole in the lower arm is actually for... It looks like it wants a socket through to make undoing the nut easy, but by now you know Lotus better than that!

 

Actually it's the only way you can center the specially sized washer while compressing the bush so the washer ends up on the ARB past the thread; by poking a screwdriver through the hole and levering on the edge of the washer while trying to nip up the bolt you can feel the washer center itself and complete tightening the nut.  

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