Shock Absorbers

Guys, I've noticed that one of my rear shocks on the CJ6 is leaking, looks like it got a smack and has cracked. They were meant to be Skyjacker +4" version that the PO purchased.

Specs are

Open 20.5"
Closed 14"

Can any steer me in the right direction on replacements, maybe part numbers as I'd like to try and source locally if poss.

The CJ6 is a 75, I'm not sure what size the eyelets are as the bushings are well worn.

Any help appreciated

Also what the difference between the front and rear shocks (they look the same) and whats the diff between early CJs and post 76 versions

 

I cannot really help, just to say that I paid for the installation of 4 blue Monroe, classic model. 2 were rapidly broken at the lower welding! And were exchanged under warranty.
So... do not hesistate to buy the best quality, even if more expensive.
I didn't discussed the price, and let the pro Jeep specialist install what was convenient.
And I consider that I could have better products, next time I'll look for better.

 

Any opinions on Rancho RS 5113 shocks

 

Some here have them and like them. Try posting on the early CJ-5 forum or even on the off topic forum regarding Rancho.

You have the pin to pin measurement, extended and collapsed. You realize that the upward movement of the axle must be stopped by the axle bumper rather than the collapsed shock absorber. I'm guessing the hanging-free measurement is longer than the 20.5" measurement you list. To pick a length, you could choose something that spans the middle of the range, or by putting the at-rest point in the middle of available travel. Then adjust the axle bumpers to limit upward travel.

If you want something like Konis or Bilstiens, these mfrs have tables of shock lengths and end types available in each series that they sell. Then you need to pick the proper valving for the shock location. I would copy whatever valving ratio the mfr recommends for that application.

 

What Tim said ^^: measure and then look at shock catalogues to find the right length shocks.

For 4" springs, 20.5 extended seems too short. On flat ground measure the distance between the shock studs (between points A and B). Lets call this measurement "Y". The formulas to find the right shock then is roughly:
1.25 x Y = extended shock length
.75 x Y = collapsed shock length

Chances are you'll come up with different lengths front and rear.

You want the shock to be around middle position with your suspension neutral...but make sure the shocks have enough movement not to max out in either direction with suspension flex. Up travel will be affected by axle bump stop length. So also measure the distance between the axle and bump stop...You may or may not already have bump-stop extenders.

Thus its good to know the spring travel up and down. You don't want to fully compress or let your shocks stop spring down-travel, or you will damage them. You can control up-travel with with your axle bump stop length...And you can also factor this in for shock length to get a little more down travel.

Personally, I like as much suspension travel as I can get (without hitting stuff) so I made some longer shock towers and run much longer shocks. This way the shocks have more than enough total travel to accommodate the full range of suspension movement...I don't need/want extended bump-stops.

If the studs/mounts are stock, the diameter for our shock eyes is 5/8"

The Bilstein website has a guide to choose the correct valving for the vehicle type the shocks are going on.

Lastly I would think the difference between the early/intermediate and late CJ shock is only length...Unless they changed the stud diameter or mounting style.

 

The PO told me that they had installed a 4" Skyjacker kit however, I never saw any receipts. All research I've done suggested you needed a 4" kit to get 33" tyres under a inter CJ6. Maybe this is wrong and it's a 2.5" lift, or even standard. All I can go off is what's there. I'll measure and check but I've never had an issue in the last 8 years

 

The main thing is - don't fit such a long shock that it bottoms before the bump stops on the frame stop the axle. If you fit 2" longer shocks, put a 2" spacer between the frame and the axle bumper. You need to look at where the axle is now and decide how much upward and downward travel you want. Without adding tall shock towers above the frame, it will be a compromise.