AVO Damper Bush Failures Polybush General Failure

[Nick Jones]

I thought you might say something like that  ;D  

I do see you your point - the design IS shite.  I'll measure up for sphericals when I fit these new bushes and get some in ready.....

 

Mine have lasted alot better than yours it seems - they were ok before the RBRR (Oct), now knackered but not completely trashed.  There is the possibility that another set of bushes will outlast the dampers themselves.  Then I will have to buy Koni and put up with the fixed spring seats  :

 

Nick

[spitNL]

Nick,

 

Couldn't you fit a sleeve to the Koni shocks?

That way you could still adjust ride height.

 

 

Frederick

[Nick Jones]

Interesting idea.  Didn't know you could get such things........

 

Have changed the bushes this afternoon.  Originals were sad but not completely trashed.  New ones are much harder compound and were a right sod to install.  However, the ring that holds the bush is 16mm wide and of that 16mm, at least 2mm is lost to circlip grooves for the spherical joint option and, worse still, in the highest load area where the ring is welded to the damper body, there is a 3mm through hole (I think as a location aid for manufacturing) further reducing contact area. The bushes don't really stand much chance.  I'm on the lookout for spherical joints and spacers....  At least my adjusters haven't seized - yet!

 

Nick

[knackerjack]

I have the ones that are blue poly bushed and they too failed twice in just a few miles so I bored out the bottom eye and fitted a thin sleeve and used poly bushes designed to fit the upper wishbones on a sprint.

I will see how good they are.

[Hurricane1500]

Just changed the ones on my AVO's after 2 years and about 25k - as the suspention is now in bits anyway  : : :

 

Have to say they look quite good really

 

No idea why that would be, maybe they have improved the material or the cars light weight has helped (might well be a bit of both)

 

mind you the shocks themseves are in piss poor condition with paint coming off and rust  ??) not that impressed for two years old

 

[DaveNotSoSideways]

The paint just peals off, basic model AVO, they are mear junk thesedays.

[Royboy66]

my front Avo after around 5k miles  :-/

 

 

put my old Koni's back on now

 

Rear Avo's still ok though.

[DaveNotSoSideways]

I'm hoping when things are clear I can spread a few jobs around the garage, 1 is to look into a few options for different shocks cause I don't like the ride on my AVO's. Its a nice bench job that could sort this problem for all (with deeper pockets).

 

There has to be a great solution there, I mean do it properly and use proper springs (not linear) and mountings.

 

For road, not a massive fan of protech either, they are racey type.

 

What we need is a proper durable damper, single adjustable. Adjustable on both strokes or supplier adjusted pre valving with no on car addjustment.....

 

I mean, do you ever want to adjust the dampers on for exampe my mothers Clio my BMW, errr, no. Why I hear you ask. Thats cause the suspension works sprung right etc. Caterhams don't have adjustables on bar the £500 each race ones.

 

Don't need it, someone did some R&D.......*sucking gasping noise*........What.......R and fucking D, would you believe it, what the hell is R&D.

 

Anyway. One pre setting for this and that. With the right springs you don't need to ask what grade cause you get ride and poise combined with the right damper.

 

Triumphs don't know nuffin about this proper job lark do they, no. They have to make do with a half arsed graft on something with 20 spring options cause none of them options actually work.

 

So nice simple dust sealed, rebuildable quality shocker you can send back and get done properly.

 

Problem is price, you won't get a damper like that sub £120each unit.

 

Incidently I'd been fascinated by torsion bars lately

 

[RustyLogic]

On the spherical bearing subject... are the circlips just used as packing? I don't see how they can latch on to the bearing to hold it in place?!

[DaveNotSoSideways]

they go in the circlips grooves threathen trading standards you get free bearings from avo, why , cause you DO have a case

[lotus62]

went to jigsaw last week, mark told me the polybush failures are a thing from the past, is he right? he showed me a rear set and the bush "ear" on the damper looks very small to me. did not buy them, still looking for a beter one but because I only do about 1000 km a year I don't want to pay too much

(the bush on my 21 year old damper still looks ok.......:-)

[spitNL]

The rear dampers never caused any problems.

It is/was the front dampers, they not only have to have to support the damping forces but also the weight of the car.

Wonder why he showed you a rear one??

 

F.

[Nick Jones]

If we are talking about the front damper and the damper eye is still the narrow one then the polybushes will still fail.  Just not enough surface area to take the load (weight of that front corner of the car plus shock loading from bumps).  Best buy Konis if you want something that will last.

 

Nick

[lotus62]

I am talking about the rear... they have never been replaced in 21years! I did do the front a while ago, replaced them for shorter stronger one's

so if I use avo's at the back I am ok?

 

[DaveNotSoSideways]

Marks version of reality is often left wanting.

[Nick Jones]

Another epic thread revival.

 

As predicted and expected, the Skip has munched through two more sets of bushes since the last report.

 

I rang Jigsaw again a few days ago and Mark once again acknowledged that there was a problem with at least some of these (just had someone else on with a similar issue - sounds like he's getting a bit fed up with it) and once again, without prompting offered to send me some more FOC. He's sent me two sets this time so maybe he's noticed a trend!

 

Anyhow, he doesn't always get great press on here, but I have to say that his service has been absolutely first class on this. These are old dampers now and the original problem is in no way of his making.

 

We discussed the likely causes (inadequate contact area) and he come up with another interesting observation, which was that on another application where very similar dampers and bushes are used in a vertical position, there is no issue with the bushes. So it seems that the angle change on this bush as the suspension moves through it's travel is also a factor and munches the bushes, presumably because it's easier for the rotational movement to occur at the OD due to short contact length rather that the ID as designed. Doesn't alter the basic issue of AVOs faulty design.....

 

Nick

[GT]

There has to be a great solution there, I mean do it properly and use proper springs (not linear) and mountings.

 

For road, not a massive fan of protech either,.........

 

What we need is a proper durable damper, single adjustable. Adjustable on both strokes or supplier adjusted pre valving with no on car adjustment.....

 

Anyway.

One pre setting for this and that. With the right springs you don't need to ask what grade cause you get ride and poise combined with the right damper.

 

Triumphs don't know nuffin about this proper job lark do they, no.

They have to make do with a half arsed graft on something with 20 spring options cause none of them options actually work.

 

So nice simple dust sealed, rebuildable quality shocker you can send back and get done properly.

 

Problem is price, you won't get a damper like that sub �120each unit.

 

Not often I quote Mr P on here.

 

The answer is proper revalved Konis if you really want it right.

 

The shore hardness of their bushes is fine, and there's no reason in the world why you would want to put a solid bush or rose joint in a spring/damper under basically single sheer anyhow.

 

If you want a clue as to why Avo is the way it is, look up the designer ROD AVO N, exactly the same bloke who did all the other cheap needle valve dampers, GAZ and PROTECH that fade and don't last.

 

Having said that, I was astonished to see just how different one "koni classic" damper is from another in what was ostensibly a brand new pair, never mind that fact, that in my opinion Koni have been making them with completely the wrong settings for the best part of 35+ years...

 

Now imagine what that means for Mr lambda in the street who goes out and buys a pair of spax, or Avo.....because he has been told by all and sundry that they are "performance dampers"!

 

I think the spring question has now been dealt with in enough detail.

[Nick Jones]

Accepted that AVO (or Gaz or Protech) are not top quality engineered. However, they do provide dampers which have adjustable spring seats and are adjustable on the car at an attractive price. Konis similar price but fixed spring seats and must be removed to adjust. I've heard one or two Koni problem stories recently (new ones), though old ones seem to be extremely durable. FWIW the old Armstrong telescopics I've got on the Vitesse (been on 23 years after 3 years on my Herald) are still absolutely fine.

 

This particular bush issue with the AVO is "designed to fail". Dave's spherical bearing is a decent solution - which I have avoided as I don't want to drill out the wishbone and thus make swapping to another type difficult. For this next bush swap I've got a couple of simple mods in mind to try and reduce the rate of attrition. When I run out of bushes next time, they (the AVOs) are going in the bin....

 

Nick

[GT]

Accepted that AVO (or Gaz or Protech) are not top quality engineered.

However, they do provide dampers which have adjustable spring seats and are adjustable on the car at an attractive price.

 

Konis similar price but fixed spring seats and must be removed to adjust.

 

Well, I've never had to adjust the height to one of these Konis unless maybe adding a bit to the top with a shim, but I don't even know where you bought your last Konis, because if you check, they are quite considerably more expensive than AVO...in fact not far short of £100 a pair more....

 

(£180 approx for Avo, which you can neither rebuild nor revalve, and don't last and fade on heavy use or at 35C or get much stiffer and uncomfortable at -15>5C)

 

(£260 for Koni, in only NS STD form, or £130 exchange for old ones to be rebuilt, almost immune to temp variations.

I charge another £220 to revalve them properly, so if you add it all up with the springs, not a fat lot of change from £600, or £430 if you can find some tired old ones to recon!)