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Luego Suspension Crush Tubes
Irony - 14/10/09 at 11:58 AM

From what I understand this topic has been done to death but I wanted some luego viento owners to give me their valuable and experienced opinions.

I have my 2 year old viento up on stands in the garage. Just started the build. I understand there is a problem with the crush tubes.

Firstly - is the crush tubes the sleeve of metal that goes inside the polymer bush. In turn that polymer bush sits insides the tubes at the end of the suspension arms?

When I got my Viento it was a rolling chassis but I have since stripped it completely and rebuilt the suspension. The suspension was very very stiff when I got it but after stripping/greasing/rebuilding it seems okay apart from a tiny bit of play on the top arms which makes me think either the bolts are the wrong size or the inner diameter of the steel liners are a mm to small.

This is what I did.

I stripped down the suspension to find no grease applied whatsoever. Suspension bolts were cranked up very tight and when undone no evidence of grease was seen. I have cleaned, polished all parts, greased and rebuilt. I cranked the bolts tight (as stated in manual) and then backed them off a quarter of a turn (also stated in manual). They move up and down smoothly now with slight (but natual feeling) resistant.

I must admit I didn't see anything wrong with the length of the steel liners but then I have little experience of this. My only worry was the tiny bit of play mentioned above.

Can any Leugo Viento owners advise me if this is normal or not?

Cheers for you replies and patience in advance.


tomgregory2000 - 14/10/09 at 12:14 PM

DO NOT BACK OFF THE BOLTS

The problem is with the metal tube that fits inside the poly bush, it is a fraction too short so the bracket on the chassis clamps the poly bush and not the tube and therefore causes the suspension to stick.

What you need to do is machine the surface of the poly bush down.

Some people cut them down with a knife others a lathe, i used a power sander and it worked or make longer crush tubes.

ALL SUSPENSION BOLTS MUST BE TIGHT

Tommy


tomgregory2000 - 14/10/09 at 12:17 PM

also have a vice to hand

What you can do is remove a bit of material, put the crush tube in the bone and clamp it in between the jaws of a vice as if it was the same as on the car and what you are looking for is a nice smooth action.


Irony - 14/10/09 at 12:27 PM

Cheers Tom

So essentially the bolts clamp the steel liners in the bracket on the chassis making it rigid and then the bushes create the cushion that the suspension arm swivels around. This makes more sense to me. AND why the steel liners are called crush tubes!!!!! Genius!

So I can either make new crush tubes or trim the bushes down. I have the hubs all off at the moment so taking the suspension arms out all AGAIN won't be to bad I suppose.


ben lord - 14/10/09 at 12:35 PM

I have said this a number of times now.
The old manual that was not written by us has many errors in it. The instruction to back off the suspension bolts is one of the worst ones. I recommend that it isnt followed very closely.
We are happy to answer email questions on building kits - info@luegosportscars.com

Regards

Ben


hector - 14/10/09 at 01:03 PM

I have noticed on my Viento in the last few months it was starting to sqeauk on the rear suspension.
So I have just stripped all wishbones off and as people say the poly bushes are slightly to long/or sleeve tube to short!!
My method of fixing them was to machine 0.2mm off each individual poly bush and my bones now fall under their own weight towards the floor with M12 bolts very tight.
Have not driven it yet but it now stands 10mm higher on the ride height just by doing this mod!

cheers colin


Irony - 14/10/09 at 01:19 PM

After a year of looking at kit cars and attending shows etc I finally decided on the Viento due to its size, appearance and large engine bay. I was about to place a call to Luego and arrange a visit. Then I was struck by some 'financial difficulties' lets say. A common financial difficulty that most men have 'problems' with. My budget was drastically reduced. But then one came up for sale second hand and I took thought that was a decent compromise for my situation. Now it looks like I have paid a price for not getting a new kit. No harm done in the long run though!!!


Paul (Notts) - 14/10/09 at 05:34 PM

The issue of crush tube size is not just a Viento issue. A lot of kit cars I have seen at shows that have "STIFF" suspention suffer from the same problem.

Paul


rusty nuts - 14/10/09 at 06:59 PM

I had this problem with my car , in fact I may have been the first to have addressed the problem . If I was doing it again rather than machine to bush I would consider reducing the width of the eye in the arm especially as my powder coating decided to fall off a year or so after sorting the bushes. It's well worth sorting the problem out as the ride is so much better , no squeeking and the handling is better. Slackening off the securing bolts is asking for trouble IMHO


wilkingj - 15/10/09 at 07:53 PM

Yes this is all correct. I did mine, but need to do a bit more on my rears (wasnt brave enough with the turning down bit)
Also use something like Silicon Rubber Grease on the bushes, I would not recomend the normal axle / wheel bearing type grease on Poly Bushes.

I got my SR grease in a tube (NOT the Aerosol version) from Maplins, about £3 a tube.
I cant see it on their website, but my local shop had it.

Agree the Bolts MUST be TIGHT. The arms should be a smooth and free movement with no side play.
If the bolts a loose, then they will move / rotate. This will wear the holes in the brackets oval, thus needing the brackets to be replaced (Welding and Jig type job). It will also give rise to handling problems if the holes are oval (movement in the suspension), and would almost certainly be a MoT Failure point due to wear in the suspension system.

Finally the bush should rotate about the crush tube. This is the bearing point, and also the bush and crush tube are replaceable (when it wears out) . This is why the tube is locked tight and should not move.


richard thomas - 17/10/09 at 05:27 PM

Does everybody else have wishbone pick up brackets that are much wider than the wishbone eye? I need to do mine and am anticipating that the new crush tubes need to be a couple of mm longer than the bushes i.e. the same length as the inside of the pick up brackets...then shim out the gap between the bushes and the brackets with washers?

Does that make sense?


rusty nuts - 17/10/09 at 07:57 PM

About time you got around to doing it Richard. The crush tubes only need to be a few thousands of an inch longer than the bushes when they are fully inserted into the wishbones NOT as long as the mounting bracket. As I said in an earlier post if I was doing it again I would reduce the width of the "eye" in the wishbones . I didn't do it that way as I didn't want to damage the powder coating but that fell off anyhow.If your powder coating is OK then either longer crush tubes or reduce the width of the polybushes. Mel


richard thomas - 17/10/09 at 08:56 PM

So i guess that at the front wishbones (where the pick up brackets are considerably wider than the wishbone eye end) the crush tubes are clamped fore and aft by the washers themselves once the bushes are reduced by a couple of thou'? I was thinking that I would have to cut the new tubes the exact length of the inside faces of the pick up brackets.....

Mel, you are correct - it is way way about time I got this sorted!!


rusty nuts - 17/10/09 at 09:07 PM

From memory I think I took about 0.030" or 30 thousands from the outer end of each bush but the best way to do it is to clamp the assembled crush tube/bush/ wishbone in a vice and check how much effort it takes for the wishbone to rotate. Ideally it should fall from the horizontal under it's own weight . Reduce each bush a few thou at a time , assemble and test until happy with results. I assemble mine with rubber grease . If the powder coating is bad you could file down the width of the wishbone eye to get the same results .


wilkingj - 18/10/09 at 10:03 AM

Remember on the front brackets you can space out the wishbones with washers to adjust the Caster Angle. The Crush tube issue is additional to this.


Irony - 19/10/09 at 11:42 AM

quote:
Originally posted by wilkingj
Remember on the front brackets you can space out the wishbones with washers to adjust the Caster Angle. The Crush tube issue is additional to this.



Having researched caster angle on here people seem to suggest that they basically have negative caster to help the car centre when doing the IVA/SVA. So like a shopping trolley wheel.

Is it best to just have a much negative caster as possible and then change after the IVA? I think from memory there are spaces for 4 washers between the 'eye' of the suspension arm and the chassis bracket.