Click on image for the lowdown. 
====
| | |
8 members (DadsFirstPickup, Jaison, Nick in Manitou, NJC, Wayne67vert, TooMany2count, Mike in Sycamore, Bill Hanlon),
79
guests, and
3
robots. | | Key: Admin,
Global Mod,
Mod | | | Forums66 Topics128,137 Posts1,056,747 Members48,454 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | I’ve had a Rotary 9k mdl SP 09-201 2 post lift in the shop for a few years and it’s always been dependable. Well time passes and when I tried to lower it today (with a car on it for about a year) from full height, it wouldn’t get off the safety blocks, allowing it to be lowered.
The pump runs but sounds like it’s not working as in it’s lost prime. Hydraulic fluid level is good, all hoses are good. A clogged filter screen or check valve are my first thoughts. No manual so I’m driving blind here.
Any suggestions? I really need to get started on another round of the 216 rear main oil leak repair game.
RonR
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Feb 2016 Posts: 1,994 'Bolter | | 'Bolter Joined: Feb 2016 Posts: 1,994 | I would suspect a stuck check valve but it would have to be "really" stuck for the pump not to be able to lift the valve off it's seat. I would bet that there is a spring loaded pressure relief bypass valve in the circuit, you might want to investigate that avenue.
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| | | | | Joined: Sep 2009 Posts: 5,980 Gearhead, Stovebolt Tech and Parts Tracker, Mod for Swap Meet and GTT | | Gearhead, Stovebolt Tech and Parts Tracker, Mod for Swap Meet and GTT Joined: Sep 2009 Posts: 5,980 | RonR, Perhaps this Operation and Maintenance manual will help you figure out the issue? There is a troubleshooting guide on page 9. I also found installation manuals available. Let me know and I can add those links. 
~ Dan 1951 Chevy 3 window 3100Follow this story in the DITY Gallery"My Grandpa Carl's Truck and How it Became Mine"1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
| | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | Thanks for the tips! I pulled the bypass valve and activated it with a small screwdriver while spraying with carb cleaner. Reassembled, Alls Good! A few tripsup/down and the safety stops are all sounding off as they should. I’m considering taking the rest of the day off. Like when working with a young horse, always end on a positive note.
RonR
Last edited by moparguy; 11/26/2024 6:56 PM.
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | A quick update on the lift just in case someone with the same issues one-day finds this thread. Once the lift would go up/down as it should I exercised it a dozen or so times. Reason being both cylinders had light leakage (they had always been leakfree) and I hoped working the cylinders would revitalize the seals as in to fix the leaks.
Foolish me.
Life happened, I left the project on the lift in the lifted position and didn't get back to the shop for a week. When I did the floor was covered with hydraulic fluid and the lift would only lower to about 2' from the floor and below the bottom lock (I had to add more fluid to get off the locks in order to lower it). Since it had a vehicle on it I just left it alone for the night, hoping it'd leak all the way down. No such luck.
I wasted a lot time online looking for solutions. The common suggestions offered was low fluid or cable problems. I did add fluid, no help. Cables were fine. And then in the light of day I just backed up and looked at things, that's when I noticed one cylinder was higher than the other. They were out of time. Think..Think.. Think... AWWW, just raise the lift to maximum height, that should force the cylinders back into time as in they're in sync.
It worked.
So now I've ordered seal kits for both cylinders and look forward to getting this little project in the mirror.
At my place setback aren't surprising, it's been a Long time since in order to fix one issue, multiple other issues have to be dealt with first.
RonR
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Feb 2004 Posts: 29,841 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,841 | At least you have a lift to tinker with- - - - -that's one of the things on my lengthy "to do" list- - - - - -Buy a lift! Haven't decided if I want a twin post frame lift model, or a drive-on. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
| | | | | Joined: Aug 2001 Posts: 3,608 Moderator | | Moderator Joined: Aug 2001 Posts: 3,608 | So Ron, what is the moral to this happy ending? Don't leave a vehicle on the lift for extended length of time? Cycle the lift on a regular basis? I'm in the process of installing a two post Champion Lift and any advice is greatly appreciated.
Don 1967 GMC 9500 Fire Ladder Truck"The Flag Pole"In the Stovebolt Gallery1946 2-Ton grain truck 1946 3/4-ton pickup, 1953 1-ton pickup 1957 1-ton flatbed dually, 1954 Pontiac Straight Eight Of all the things I've lost in my life, I miss my mind the most! | | | | | Joined: Feb 2016 Posts: 1,994 'Bolter | | 'Bolter Joined: Feb 2016 Posts: 1,994 | Something does not seem right, the locks should hold the weight, not the cylinders/hydraulic pressure. I can understand if one cylinder was actually holding some weight, that could force fluid past the bad seals. Or was it just gravity and the seals being at a low location?
1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy
| | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | So Ron, what is the moral to this happy ending? Don't leave a vehicle on the lift for extended length of time? Cycle the lift on a regular basis? I'm in the process of installing a two post Champion Lift and any advice is greatly appreciated.
Don Don, you hit the button on the head. Cycle the lift occasionally. One of the lift's jobs is to provide additional car space, the 70 340 Duster lives under whatever is on the lift most of the time. What I should have done (I think) is every time I drove the Duster I should have exercised the lift. I try to drive it at least every couple months. A trip to Sheridan is about 40 miles round trip, plenty to get fluids and all up to temp, boiling off moisture. With the Duster out of the way, running the lift up and down a couple times would have been so easy and perhaps prevented the seals from drying out and eventually failing? You're going to love your new lift. The only bad about getting a lift is all the bruises from kicking yourself cause you waited so long! RonR
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | 78buckshot said "Something does not seem right, the locks should hold the weight, not the cylinders/hydraulic pressure."
And that's exactly what happened, as long as the locks were engaged. When I walked into the shop after being away for a week, the lift was still elevated, sitting on the locks as I always leave it. However there was a huge fluid deposit from leakage on the right side of the lift (side with the motor/pump/reservoir). After adding about a half gallon of fluid and raising the lift off the locks, it would not lower all the way. It did go down below the lowest lock, but stopped about 2 feet off the floor.
When the lift was sitting in the "almost" totally lowered position as described above, the right side cylinder was practically bottomed out and the other cylinder was at almost full extension. Raising the lift all the way forced both cylinders into the full extended mode and then they both lowered all the way after retracting the locks and hitting the down valve.
I should probably draw out the hydraulic circuit to better understand what's going on, but haven't (yet).
RonR
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Oct 2012 Posts: 340 'Bolter | | 'Bolter Joined: Oct 2012 Posts: 340 | Just a note, if buying a lift they all don't go to the same height. If you are a all person, I'm 6'3" I wanted one I could work under without having to be bent over all the time. Sometimes I need to lower it a few inches so I can get at some bell housing bolts or to something on top of a fuel tank.
1936 GMC T-14 restro-mod
| | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | I totally agree with FAST55. That said, for a as yet unexplained reason, I find it pretty nice to sit in a roll around office chair when doing a lot of work under vehicles these days.
RonR
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Sep 2009 Posts: 5,980 Gearhead, Stovebolt Tech and Parts Tracker, Mod for Swap Meet and GTT | | Gearhead, Stovebolt Tech and Parts Tracker, Mod for Swap Meet and GTT Joined: Sep 2009 Posts: 5,980 | RonR - Now that's working with comfort, especially for those of us with much less flexibility than we had as young'uns. 
~ Dan 1951 Chevy 3 window 3100Follow this story in the DITY Gallery"My Grandpa Carl's Truck and How it Became Mine"1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
| | | | | Joined: Aug 2001 Posts: 3,608 Moderator | | Moderator Joined: Aug 2001 Posts: 3,608 | Ron that's what I thought, that it should be cycled about once a week to keep the seals from drying out. Now what I also think is, that if it has been extended and on the locks for over a week, to run it up high, if you can, to get the cylinders in time again. Is that thinking right?
Fast, I used to be 6' 3" but with age I'm down to 6' 2" now and I did get the tall lift. A wore out office chair is also on my radar to find. Maybe one with a head rest for when I need a break?
Don
Last edited by 2-Ton; 12/14/2024 10:24 PM.
1967 GMC 9500 Fire Ladder Truck"The Flag Pole"In the Stovebolt Gallery1946 2-Ton grain truck 1946 3/4-ton pickup, 1953 1-ton pickup 1957 1-ton flatbed dually, 1954 Pontiac Straight Eight Of all the things I've lost in my life, I miss my mind the most! | | | | | Joined: Sep 2013 Posts: 1,367 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,367 | Don, you’re not wrong. But perhaps a bit too cautious. My Rotary lift is many years old (20?) and until this episode it’s never had any problem sitting for a month or two elavated to the max and sitting on the locks. Bump it up a couple inches, release the locks and lower. No problem.
The issue I think this time is…it may have been a year or at least many months since I’d touched it. Due to the CJ 5 project, truck and tractor maintenance as well as doing three complete AC rebuilds this year (along with normal county life) I neglected a few projects. Including the one on the lift. My bad.
RonR
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear 1970 340 Duster 1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain) 1964 CJ5
| | | | | Joined: Apr 2005 Posts: 2,832 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 2,832 | We have two Rotary lifts, a 9000# two post and a 12,000# drive on. My advice on selecting one is go by your age; a two post is fine if getting down on the floor to set the arms is no problem but the drive on is the cats meow for old farts. We use air jacks to lift off the safety stops when stuck. Be sure to lift and lower evenely. Our drive on has the rolling jack option for brake or front end work but again an air jack would work.
Evan
| | | | | Joined: Apr 2005 Posts: 7,441 Bolter | | Bolter Joined: Apr 2005 Posts: 7,441 | I have a fairly cheap 4post drive on lift which sets outside 24/7 and has for about 6-7 years. It gets worked fairly frequently and the only trouble I have had is rotten hydraulic hoses. Replaced all 3 and it’s back to working fine. 2 weeks ago I bought a 4 post 18,000 drive on rotary lift. It will also reside outside next to its little brother. $250 so I couldn’t refuse it. I’m hoping this thread has educated me enough to have many trouble free years of usage. Thanks all for you insight.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
| | |
| |