Shed a bit cold this weekend so I thought I would rebuild my front dampers. I bought 4 secondhand Penske units some time ago. I did not notice quite what a bargain they were. They are 4 way adjustable and owner rebuildable. In fact they come apart with a pin wrench and a couple of spanners.


Shocks


Shocks

Two out of the 4 I bought had identical shims and pistons so I have built them up using the best bits. All good fun but I have some questions for the experts....


(1) I have no starting point whatsoever for valving so am I right in thinking that as a very rough start a higher spring rate will need stiffer shims to keep it under control?

(2) Refilling the shocks with oil looks messy but not over complicated. The Nitrogen is more of an issue. I could rent a bottle from BOC but does anybody know of a friendly person with a regulator (200psi) who would help with this bit without insisting on doing a service?

(3) last question is where can I find anybody selling clips like the photo below...my googling skills have failed me....what is the common name?

Can't help with question 1 but you may find some tyre companies have nitrogen gas and the correct regulator??
The clips look like wire circlips

Hi,

Is it some sort of Circlip?

Can you google shock absorber circlip

I'd just fill them with air while you're testing. The temperatures you'll probably be looking at, I doubt it will make any difference.

I would stick 120psi of moisture free air (compressor with moisture trap) in until I know i wouldn't have to take them apart regularly. 200psi sounds a bit excessive anyway.

Many thanks guys - you are right filling with air - which is after all 79% nitrogen seems like the go

As for the circlips all googling has failed to find any retail source...

Hi try these guys
http://www.springmasters.com/circlips.html
The clips are called snap rings

Hi,

Best of luck building your shocks.

1 Heavier springs will require more damping so more/thicker shims.

2 I have never used air instead of nitrogen. I'd be concerned about strapping four potential bombs to my car to be honest. The reason nitrogen is ued is because it is inert. 200 psi is high but not unreasonable. 10 bar is a widely used pressure but the ideal pressure will depend on stroke, spring rate and what you are using the shocks for.

3 You need some Round Wire Snap Rings. Google will help you here.

quote:

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Originally posted by MikeCapon
Hi,

Best of luck building your shocks.

1 Heavier springs will require more damping so more/thicker shims.

2 I have never used air instead of nitrogen. I'd be concerned about strapping four potential bombs to my car to be honest. The reason nitrogen is ued is because it is inert. 200 psi is high but not unreasonable. 10 bar is a widely used pressure but the ideal pressure will depend on stroke, spring rate and what you are using the shocks for.

3 You need some Round Wire Snap Rings. Google will help you here.

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Hi all

many thanks for the advice - spring clip thingies now purchased minimum order of 24 so I have a spare or...20 if anybody needs one

The 200psi figure is the starting point recommended in the Penske owners manual - the reservoirs are marked max 300psi. There is a separator piston between the oil and gas.

I have used a shim pack half way up the range to control 600-700 lb/inch springs. We shall see once this thing finally turns a wheel.....

As said, I suggest you try and find some nitrogen. It is used to stop you combusting any oil mist that may be present, same as in gas struts and the like (where temperature definitely isn't a concern, e.g. office chair!)