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MG Midget and Sprite Technical - Armstrong shock absorbers

I just bought a pair of refurb Armstrong front shock absorbers for my midget and was wondering...

The resistance on the shock absorber seems to be different depending on which direction it is moving. When moving up (as if the suspension spring is being compressed) there is hardly any resistance. On moving down (the suspension spring is returning to it's normal posistion) there is plenty of resistance.

Is this normal, or should equal resistance be felt when moving the shock up as well as down? It's a while since I replaced the back shock absorbers but from what I can remember, I thought there was resistance in both directions of travel.
T Hamilton

Id say stand them in a corner in the correct postion for a while....they wont work correctly if they are sitting oddly
Prop

Hi Prop, tried that.... I mounted it on the car yesterday. I have tried moving it throughout it's travel 10+ times in the hope that any air bubbles will be dislodged.
T Hamilton

Hmmm, could be a faulty refurb unit. I just tried the other unit clamped in my workmate, and there appears to be some kind of equal resistance in both directions of travel.

The other clue on the suspect unit is that it is extremely difficult to move the shock absorber down (requiring me to almost hang off it), but next to no resistance on the up stroke.

I feel a call to the supplier tomorrow could be a good idea.
T Hamilton

I do remember my apples where some what easy to raise up but hard to push down....so you maybe okay

what did it drive like?

Prop
Prop

How much did you pay for your recons?

The price some people charge barely covers the cost of cleaning and painting.
Dave O'Neill 2

£18 each, I guess maybe you get what you pay for...
T Hamilton

blimey a tin of paint to paint them and the oil to refill em costs damn near that.
roy judd

It's quite normal for dampers to have a lower resistance in bump than in rebound as in rebound the spring is forcing the wheel doing. I would be worried about the differing characteristics between the 2 sides though. They do need to be held in about the right orientation and moved through their travel to make sure the fluid is in the right place. As others have mentioned though it is difficult to see what sort of proper recon can be done for £18.
David Billington

They're from the MGOC. I phoned them today and there were no questions... another one is in the post. As you say, probably no more than a tin of paint and oil refil. I can't see they can do anything else for that, although I would have thought that they would have at least tried them before sending them out. It was the fact that there was next to 0 resistance on the bump that was the reason I was replacing my existing shocks in the first place.
T Hamilton

David, is correct, it's usual for the shocks to have different rates on compression and rebound. Two reasons, one is the valve and it's springs give different rates in each direction, the other is the actual configuration of the pistons inside the shock. Most have one piston with a rubber cup type seal and the other has a split metal ring which doesn't seal as well, hence more fluid bypass when that piston is moving the fluid.
Bill Young

T Hamilton,

It's that kind of quality refurbishment that led me to design a telescopic damper/upper link replacement back in 1987 as I got pissed off with cheap recons that were little better than the dampers they replaced, seems that more than 30 years later not much has changed. Maybe someone should import a container load of Peter Caldwell recons or license the process or do it properly in the UK.
David Billington

Yup, we've got the best dampers in the world, here in the colonies (Peter's rebuilds). But you've still got the best beer over there!

Norm
Norm Kerr

How about a trade


A bunch of our peter cardwells for a bunch of your type 9s....or K-series

Prop
Prop

Prop, Peter is already selling his shocks in GB, I think it's Peter May who was handling them. Too bad though for you, now you've nothing to trade for that K series or type 9.
Bill Young

I saw those Peter Caldwell shocks on Peter May's stand at Race Retro

Impressive

So was everything else on Peter's stand...
bill sdgpm

each time i see those adjustable Peter Caldwell shocks i want to switch my FL (i know borowed design) setup for those with a toplink kit and a set of neg camber trunions.
Onno Könemann

I have been in Peter C's shop several times in the last year. I can say this, if you think his shocks look good on the outside you would be very impressed with the inside. They are truly and properly rebuilt.
tomshobby

Just for grins, go here:

http://www.flickr.com/photos/safety_fast/2619658351/in/set-72157605873860590/

That pic, and a few that follow, show Peter Caldwell's exhibit table at 50 Years of Spridgets a couple of years ago, along with the man himself during his excellent tech session. There are some close-up shots of his adjustable damper conversions. None finer!

-:G:-
Gryf Ketcherside

What Peter might not tell everyone is that he did a lot of research before starting to rebuild shocks. He also had help from experts in different fields help work out a process. One of the guys that did a lot of work on the project, now retired, is a PHD in metallurgy. I taught in a machine tool program and knew this guy, he was absolutely brilliant. We had the only metallurgy lab I know of anywhere in the world with an electron microscope. We could actually see individual molecules in metal with it. Just a point of interest, it was not used on this project.
There is a good reason why Peter's product is such good quality.
tomshobby

This thread was discussed between 11/04/2010 and 16/04/2010

MG Midget and Sprite Technical index

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