I just bought a camper with Happijac hydraulic jacks. One leaks where the ram exits the jack. At the exit point is a very large 'nut' with an o-ring, a kind of brush like seal, and another seal that fits right at the top. Hydraulic fluid is leaking out around the ram where it seals at the nut. The seal right at the top was obviously deformed.
Would it be an adequate repair to replace all the seals in that 'nut'? I ask because I'm not sure whether hydraulic fluid should be getting that high up in the cylinder and whether there is another failed seal of some kind at the base of the ram.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

You'd have to define the term "adequate repair" =)

If it were mine - yeah, that'd be fine - I assume that the jack is used on an occasional basis, and if one failed in the field, then you'd be able to deal without it or have a backup available.

If its a constant use thing (ie- you MUST use that jack to level and the entire weight of the camper rests on the jacks full time when parked), I'd splurge for a new jack altogether. I don't think that there are any other seals in a jack (other than the ones in the pump/pressure source) but if those seals got damaged, what else is damaged internally ? (bad fluid, junk in the fluid...)

I have no camper experience, just a few old floor jacks that I have taken apart in my garage.

-John

-John

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2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)

I found a manual for the jack and it said if it leaked there, replace the seals I described. Now I have to find the seals.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Call a fork lift repair shop.

Kerry, if you can't conveniently turn up the parts you need, then you might try contacting the folks at Otto Service (hyjacks.com). If they don't have the parts, they might be able to point you in the right direction.

I've never done business with them, but I contacted them with some technical questions when I was considering purchasing a used engine hoist (on eBay, not from Otto Service - I wanted to know what my options might be if I had to rebuild or replace the cylinder). The guy was very helpful.

I really like their web site, too - lots of (for me, at least) interesting information.

Thanks for that link. Lots of good info there, I like the animation of a hydraulic jack.
He says that leaks at the main piston indicate problems further below which is what I was thinking might be the case. However the Happijac's may function differently. When I removed the main piston/ram I didn't see any obvious sealing devices at the bottom, there was a large plastic piece called a bushing but I didn't see any real sealing function.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Lucky for me, www.rocketseals.com is only about 5 miles from my house. Took the jack over there and they supplied me with all the seals to rebuild the gland nut on all 4 jacks for $28. There are six separate sealing rings in each nut. One was a fat felt one. They didn't have one so they gave me a similar sized rubber one. It was very hard trying to get the rubber one in place of the felt one so I re-used the felt one since I couldn't imagine how felt could play a crucial role compared to the rubber o-rings. So far it's holding up.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

kerry, unrelated to your thread but re: your camper-do you have a site/pictorial on your build up? I'd be interested in seeing how you're coming along if you do. It's something I've considered in the past, just never had the money to do it.

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1980 300TD-China Blue/Blue MBTex-2nd Owner, 107K (Alt Blau) OBK #15
'06 Chevy Tahoe Z71 (for the wife & 4 kids, current mule) '03 Honda Odyssey (son #1's ride, reluctantly) '99 GMC Suburban (255K+ miles, semi-retired mule) 21' SeaRay Seville (summer escape pod)

I'm been posting info over on Expedition Portal but I haven't been able to upload pictures since I got the truck. It's got the same forum software as this site but the upload feature is broken. Don't know when it will be fixed.
I've leveled the bed in the truck, installed tie down points, purchased the camper. Now I have to remove the oil tanks, and cut out a section of the service body so a jut in the body of the camper will fit.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13