TR4/4A Differenc e between TR3 and TR4 lever shocks?

[TR4nut]

I have a collection of lever shocks in various states and am trying to pick the best set for the 3A - to me, the TR3 and TR4 shocks look identical (admittedly only via a casual inspection). Does anyone know the difference in these shocks? World wide auto in Madison shows them as two different items.

 

[TR4]

I thought the TR2 thru TR4 rear shocks were the same but the TR4A had a different lever length (shorter I think?) due to different links being used. Look at the length of the levers and also look at the mounting holes to see if they line up with your car.

 

[TR3driver]

They do interchange physically, so I would guess that the difference was in the valving. My TR4 SPC lists no less than 7 different pairs of shocks just for the TR4! The TR3 shocks are listed as being for TR4 between CT3434 and CT11478, all countries except USA.

Randy, IMO the most important thing is that the pair of shocks you choose are the same stiffness. Try bolting them face to face and clamping in a vise or whatever, so you can compare stiffness in both directions. Trying to measure it is difficult, but just comparing is easier.

 

[TR4nut]

Good idea, thanks Randall - I was guessing it might be just valving but it makes sense to try to do a quick bench comparison first.

 

[vivdownunder]

To identify between the rear shockers, the TR2-4 type has the lever arm cranked away from the shocker housing. The TR4A type has the lever cranked towards the shocker housing with a bump stop part way along.

Providing the valves and seals are OK, for an acceptably matched pair, drain and refill with Castrol Hyspin AWH68 fluid. Or there's Moss Shocker Fluid in 16 oz bottles. To fill a shocker it's best to clamp it in a vice as mounted on the car, and only fill to the bottom of the filler hole. Do not lay on its side and fill or it will have too much fluid and blow out the seals.

Viv.

 

[PeterC]

TR3 shocks are numbered 6058RH/LH
TR4 shocks are numbered 7999RH/LH

These numbers are stamped on the lower edge of one of the mounting ears.

They are fully interchangeable as they have 3-5/8" center to center bolt spacing. The 7999 has a slightly beefier casting, and the rebound spring is cranked a little tighter. The castings on the arms may be different,too. The earlier shocks seem to have a more rounded arm, whereas the later were squared off. These are called Armstrong DS9 style. They suffer most from having the mounting hardware not tightened, and thus wear the holes in the mounting ears. These are all zinc castings. As it's difficult to get a socket in there (thin wall is bets) a very good solution is to use socket head screws, and check/tighten every oil change or so.

TR4As use the same shocks as 5s/250's and 6's. Larger body. Bolt spacing 4" Piston diameter larger. Valves slightly different. Arm is bent and has a rebound rubber pad cast on the arm. These are Armstrong style DS10. Part number stamped is 8686LH/RH

Hope that helps.

Peter C

 

[TR4nut]

Hope that helps.

Peter C

Peter-

That is perfect - I forgot you were on this board, thanks very much!

Randy