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post #1 of (permalink) Old 10-03-2001, 10:07 PM
thillsam
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cheap shocks...

Ok, here's what happens when I get to putting off my homework and domestic chores...

I wanted stiffer valving in both front and rear shocks on my RS5k-equipped-but-otherwise-unlifted-suspension '86 Toy 4x4 short bed. Being a broke college student, and taking a class in fluid dynamics, it ocurred to me that I could cheat the money=better suspension equation by putting thicker oil in my existing Rancho RS5k shocks. We're in the chapter about viscosity...

After considerable study and analysis of the twin-tube shock design, I decided to drill a 1/4" hole into ONLY the outer chamber of the shock body, just below the seal. After cleaning up the lost oil, I found that the valving between the inner and outer reserviors of the shock kept me from bleeding all of the piss-thin fluid out of the inner compartment/bore.

Another hole, this time much smaller (.045) went through both walls of the shock, as near to the end of the main body, right beneath the eye, as possible. This would only allow flow to let the fluid out and not be big enough to bother valving(compression) too much. The rest of the oil came out in a nice, toolbox-coating(yes, I did) stream when I pushed the shaft in for the final time. It was purged.

I then tig welded a little tiny 1/4" pipe nipple cut in half over the bigger hole, near the seal. While I was at it, I plug welded the little hole in the other end.

While I was at Ace getting the 2 nipples that I cut in half(1 end for each shock), I bought a 1/4" pipe to hose barb.

I threaded the barb onto my new filler port, and looked around the shop for some thicker fluid.

10w-40? no, too thin still. 90w-140 hypoid? yeah,...just right. In a convienient squeeze bottle too.

On went the hose and I began re-bleeding all the air out of the shock, replacing it with virtual molasses. After it was all bled, it felt like a RS 9k set on about 4...pretty damn stiff and ready for airtime.

On went the 1/4" pipe plugs and off to test...stiff, just right tough.

2feet...then 4 feet of air didn't blow out either the valving or the seals, yet.

Has anyone else tried this?

Any suggestions?


YEEEEEEEEEEEEEEEEEEEEHAAAAAAAAAAAAAAAAAAAAAAAAAAA!
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post #2 of (permalink) Old 10-03-2001, 11:29 PM
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Re: cheap shocks...

Doh! all over the toolbox! Do you have any pictures or diagrams? Sounds like something Iwould like to try. Would it be possible to add remote reservoirs?

Dean
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post #3 of (permalink) Old 10-04-2001, 12:51 AM
thillsam
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Re: cheap shocks...

Yeah, the nipples I welded on the side are NPT connections, good for 200 psi or so. You would have to make your own reservior though...I haven't come across an easy way to make/adapt another device with a floating piston adn all that, that would hold the pressure. You *might* be able to use a low pressure pneumatic cylider, and just let the shaft move a little as the oil displaced the gas. You could just charge the one side with compressed air or nitrogen, whatever's cheap.

Read my other post on the Toyota Truck & SUV board...tomklipp's respose makes soime valid points about using the oil I did. But hey, all I had in the whole deal was 4 hours and about $14.

They do work good, in parking lot romps. I haven't taken them out and really put them through some long, whooped out raods to get them real hot either. There's a good little launcher jump in the inlet to the parking lot where my shop is and I've hit it several times, faster each time, and finally bottomed it at about 30mph. I estimate 2 feet of real air, and a cushy landing.

It's a little stiff around town...like I say, its about like my friens truck with RS 9ks set on 4 or 5.

You could change this with lighter oil, or by drilling more bypass holes. I was thinking of a way to valve them just like a real bypass shock, but the check valves and needle valves you'd havta buy would put you over $50.

Another note: you wouldn't hafta use Rancho shocks. Any twintube shock from anywhere would work. I recently went by the local showtruckliftemup shop where all the Rancho and ProComp stuff is sold, and asked about the shocks they take off of the trucks. They put the m in the dumpster out back, and said I could have them alll. I got a bunch of PowerStroke 4x4 shocks, valved pretty stiff already. More for experimentation...


YEEEEEEEEEEEEEEEEEEEEHAAAAAAAAAAAAAAAAAAAAAAAAAAA!
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post #4 of (permalink) Old 10-04-2001, 12:51 AM
thillsam
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Posts: n/a
Re: cheap shocks...

Yeah, the nipples I welded on the side are NPT connections, good for 200 psi or so. You would have to make your own reservior though...I haven't come across an easy way to make/adapt another device with a floating piston adn all that, that would hold the pressure. You *might* be able to use a low pressure pneumatic cylider, and just let the shaft move a little as the oil displaced the gas. You could just charge the one side with compressed air or nitrogen, whatever's cheap.

Read my other post on the Toyota Truck & SUV board...tomklipp's respose makes soime valid points about using the oil I did. But hey, all I had in the whole deal was 4 hours and about $14.

They do work good, in parking lot romps. I haven't taken them out and really put them through some long, whooped out raods to get them real hot either. There's a good little launcher jump in the inlet to the parking lot where my shop is and I've hit it several times, faster each time, and finally bottomed it at about 30mph. I estimate 2 feet of real air, and a cushy landing.

It's a little stiff around town...like I say, its about like my friens truck with RS 9ks set on 4 or 5.

You could change this with lighter oil, or by drilling more bypass holes. I was thinking of a way to valve them just like a real bypass shock, but the check valves and needle valves you'd havta buy would put you over $50.

Another note: you wouldn't hafta use Rancho shocks. Any twintube shock from anywhere would work. I recently went by the local showtruckliftemup shop where all the Rancho and ProComp stuff is sold, and asked about the shocks they take off of the trucks. They put the m in the dumpster out back, and said I could have them alll. I got a bunch of PowerStroke 4x4 shocks, valved pretty stiff already. More for experimentation...


YEEEEEEEEEEEEEEEEEEEEHAAAAAAAAAAAAAAAAAAAAAAAAAAA!
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