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JohnD

Damper refurb - or not?

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Just received back two AVO front dampers, adjustable for height and stiffness, that I had sent them.  They'd been in place ten years at least, and the adjusteknobs felt very squishy.

Now they're back, nice new bushes each end, but they don't feel very different.   One adjuster has 16 clicks the other 12, and I can't feel much difference in stiffness in either max setting.     Would you send them back and ask them to look again?

John

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My AVOs are in the virtual bin (under the bench) having munched their 4th set of bushes, but also with substantial side play in their piston rods and a fair sized leak from the seal on one of them.  I was also finding I had to keep turning them up to maintain damping. These are the later type with the narrow “designed to fail” bush rings on the bottom. Forget the exact mileage, but not very much - under 20k. I did think about sending them for refurb but decided I didn’t like them enough.

Replaced with Konis which, apart from lacking adjustable spring seats and on-car adjustment, are vastly superior. Some have good things to say about Gaz - no personal experience.

I would definitely query the difference in clicks - how are you supposed to ensure even adjustment like that? Also ask what they’ve actually done to refurb them.....

 

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Worth giving them a ring.  I've always found them to be very helpful..  I've got pairs of them on both my racing Clans and have had no problems with them,

Pete Richards

p.s.  Debating whether to leave ST as it has little interest for me now as it has become a mainly Triumph forum.

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Parcelled the dampers up with a letter, and emailed AVO's office.     Mail them first thing tomorrow, won't get them to Northampton as quick but they'll get the message tomorrow.

Bit POed as despite Nick's experience, I've always heard well of AVO.

John

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I had AVOs all round on my Spit and found the adjustable spring seat on the fronts very useful.  Like Nick though, the fronts suffered from rapidly wearing bottom bushes due to the stupidly small contact surface area in the bottom mount. This was resolved, with a tip from Markus, using a rear spring-eye bush instead.  Shortened slightly in the lathe (about 1.5mm taken off) they are a perfect tight fit and, being encased in a steel tube, last for ages, at least 7 years so far.

The rear AVO's lower fixing is not so easy to upgrade. Mine started rattling when the steel tube started fretting on the lower mounting stub/spigot of the upright and got worse the more it wore the upper and lower surface of the stub down.  Plus, of course, you also have the same bush wear problem as it has the same small contact area as the front ones.  I can't think of a proper fix for this, so have gone back to using standard dampers with the large eye and double rubbers on the rear. 

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17 hours ago, PeteClan said:

p.s.  Debating whether to leave ST as it has little interest for me now as it has become a mainly Triumph forum.

Please don't I have valued your input, maybe the competition/car prep sub forum, although quieter might be more focused?

Alan

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I hope its not the "refugee problem" that's driving you away, Pete.     Most of our new recruits are fromn TRR and CT, so, yes, Triumph orientated, but as Alan says, your opinions and experience are valuable in this wide-open forum!

Post something that interests/ troubles you, and see the response!

John

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The only reason we are Triumph oriented is that the currrent posters are mostly Triumph oriented and you leaving us really wouldn’t help with that. NonTriumph input is very welcome, so don’t leave, bring your friends over! We need more like you!

Nick

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21 hours ago, sparky_spit said:

I had AVOs all round on my Spit and found the adjustable spring seat on the fronts very useful.  Like Nick though, the fronts suffered from rapidly wearing bottom bushes due to the stupidly small contact surface area in the bottom mount. This was resolved, with a tip from Markus, using a rear spring-eye bush instead.  Shortened slightly in the lathe (about 1.5mm taken off) they are a perfect tight fit and, being encased in a steel tube, last for ages, at least 7 years so far.

The rear AVO's lower fixing is not so easy to upgrade. Mine started rattling when the steel tube started fretting on the lower mounting stub/spigot of the upright and got worse the more it wore the upper and lower surface of the stub down.  Plus, of course, you also have the same bush wear problem as it has the same small contact area as the front ones.  I can't think of a proper fix for this, so have gone back to using standard dampers with the large eye and double rubbers on the rear. 

Hi all

Still not tested and not sure how noisy or how long they will last, but I replaced the bushes on my AVO rear shocks with spherical bearings, more compliant with the offset issues, and easy to align.

IMG_2828.jpg

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Yes that is an option.....  I know that Dave S did similar on his AVOs in his Spitfire six or seven (?) years ago but I don't know how well they lasted or how noisy they became. It will be interesting to hear how you get on with them for a road car.

Putting spherical bearings on my rear lower mounts would still use the same spigot and might rattle just like the existing steel tube does, unless I can refurb the spigot upright of course. I'm thinking of trying a rear spring-eye bush again, shortened and with the central steel tube drilled out and with a new larger, correctly sized one turned up to ensure a tight fit on the spigot. It will be much firmer than standard but not as rock solid as sphericals.

Maybe a job for when the rear end is apart again.

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They won't rattle on the front as they are under load in the same direction all the time.  Not always the same load, but always the same direction.

On the rear, Mark's should be the same due to the spring on the damper.  Damper only - it will probably rattle and clonk after a while as the load direction will be constantly changing

Nick

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AVO returned my dampers, with the adjusting knobs now allowing an equal number of clicks, whihc they attributed to the springs behiond the knobs.    But the damping force on each is still very different when hand compressed!    I rang  them and spoke to 'Nigel' who had written an explanatory letter about the adjustment to enclose in the parcel.    He says that this difference is due to the 'slow-speed' leak of fluid, through a non-adjustable valve, and that my dampers have been on their test rig.   He guarantees they are equally adjusted for the fast changes that occur in suspension movement, and that the obvious difference in the hands is not important.   

I can only take his word for it, but I have to say, I'm not very happy.

John 

Edited by JohnD

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So he’s basically admitting that the valves don’t seal properly. What he says about fast changes has some weight to it - the leakage will become an insignificant proportion at the fluid flows caused by higher speed stroking, but still seems like it might well reduce damping for slow oscillations and maybe take the edge off the damping effect. Whether this actually would have a detectable effect on the car...... I have no idea.  Feel that the fact they are noticeably different is more significant than the fact that there is a bit of leakage.

Koni....... though as a racer you will miss the adjustable spring seats and on-car damping adjustment more than I !

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Local  KwikFit offers damper testing.   I'll refit and get it to.them.

it might be more reassuring if AVO offered a print out of their tests.

John

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I really wouldn’t expect anything more elaborate than a leak check and bounce test at Kwikfit.

I made the mistake of making an appointment with their air conditioning “specialist “ once. I don’t know much about automotive air conditioning but I know more than he does........

How much do Avo charge for the service?

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Gaz have sensible bottom bush. VAT included in above price. Konis £139.

Must say that I’ve been really impressed with the Konis even though they caused me some aggro finding springs due to the loss of adjustable seats. Mind you, the new springs were part of the win.

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