Thread: Rebuilding the red Rover jack

Repairing a Rover Jack.
This is not a Rebuild a jack for dummies instruction set, I've assumed that you know how to pull and replace seals, know how to use a hammer and drift in place of a pin spanner and have at least a rudimentry understanding of hydraulics and the precautions required with them...

That said... For those of you who want it P38arover is currently converting this thing from a word format to .pdf for me and ATM I have it as a word file and a HTML zip file complete with images.

The Disclaimers and stuff belong here. You do this at your own risk, cost and all that other gumpf.

This primer is split into five sections;-
Intro/disclaimer
Testing/Fault finding the jack
Repairing the lifting side
Repairing the pumping side
Reassembly

The jack depicted has been bodgied previously and correct repair will require either purchasing the correct tool or a different replacement seal screw seal.

Read the entire instruction before starting any practical work, other than a small seal pick you do not need any specialist tools.

To get replacement Seals take both sides of the component the seal is to fit with you to somewhere like Pirtek or Norseal and show them the component when you ask for the seal. Don’t just take the old seal with you as the rubber type seal will be soft and expanded and the re-enforcing nylon/teflon seals will be crushed or distorted during removal. Pay close attention to the orientation of seals and supports as incorrect installation may result in a non-working jack or a working jack that will fail prematurely

During assembly hold balls and valves in place with a coating of white petroleum jelly (vaseline) and coat all seals/components with appropriate oil prior to assembly

Teflon thread tape on the sealing screw can assist with leak control.

If your jack is only a single piston type disregard the Top piston section of fault finding and fault find as for the bottom piston.


Testing/Fault finding the jack


Clean the jack, ensure that the jack is correctly filled and then raise a load to the maximum height of the jack. If you lift to the stops and the pump handle is up lower the jack a little and depress the handle to the down position. 90% of jack leaks are from the filler plug, when storing the jack, lay the jack down so the filler plug is uppermost

If the jack won’t rise, remove the lowering screw check it and its seat. Clean Replace Refill Repeat. It’s highly unlikely this is the fault but it must be checked. If the jack still will not rise then one of the one way valves in the pumping cylinder is faulty.

If the jack creeps down and/or forces fluid out of the top of the bottom lift piston then the top piston seal is faulty and the jack is not typically easy to repair at the handyman level so is not covered in this instruction.

If the jack creeps down and/or forces fluid out of the bottom lift piston then both the main lift piston seal and sealing screw seal are faulty.

If when the jack is laid down fluid leaks out of the neck of the cylinder then the tank seal is faulty
If the pumping handle will not stay down then the pump valve is faulty.

If fluid leaks out of the pumping piston then its seal is faulty.


Repairing the lifting side

Lower the jack, drain the oil and Place the jack in a vice. As this jack has already been repaired there is no Before shot for the sealing screw.



1. By hand pull the lifting piston up about half way to allow easy access to the sealing screw. This should be recessed unlike the photo, which shows a previously butchered item.




2.Using either the correct pin spanner or a hammer and pin punch/drift/chisel turn this anti clockwise about 2 turns, then grasp with vice grip pliers and unscrew completely.



3. Withdraw the piston from the cylinder use a seal pick to remove the seals.





The damaged seal just below the seal screw on the piston in image 2 can be replaced with a square seal, or an o ring with a nylon/teflon backer. Alternatively clean up the damage done to the sealing ring on removal. If you install a backer and o ring combo it must be installed with the backer nearest the seal screw.
Clean everything and replace the seals. Proceed to assembly and testing[/OL]

Repairing the pumping side

1.Remove the E clip and pin that retains the rocking arm + pumping piston


2.Remove the rocker arm + piston
3.Remove the pump body



4.Remove the check ball, inspect its seat and screw a brass screw into the check valve body then withdraw the check valve (has the large hole) The check ball seat can be cleaned up with a blunt drill bit that fits and valve lapping paste

5.Remove the seals from inside the pump body and the brass sealing washer.



Inspect the external seals on the check valve If these are not the fault with the check valve replace the jack, initial repair of the check valve can be time consuming and may require several attempts to get right.
6.Clean everything and replace the seals. Proceed to assembly and testing.



Assembly and Testing
Assembly is the Reverse of disassembly.

Some tips

When assembling the internal seals to the pump body insert the piston and rocker arm assembly from the bottom until the face of the piston is level with the bottom of the seals groove.



Prior to installing the lift piston compress the top piston fully into the bottom piston, fill the cylinder with oil from the top then open the lowering valve, insert the piston assembly just far enough for the larger diameter on the lifting piston to just clear the seat for the sealing screw seal. Install the seals then screw in the sealing screw, open the lowering valve fully and lower the cylinder. This will aid bleeding the jack.


To bleed the jack, fill so that with the jack vertical oil is just present at the filler hole, pump the jack up and install the plug, turn the jack upside down open the lowering valve and compress, Repeat twice. Check oil level then test jack as per fault finding

Vert timely that this thread should be bumped from oblivion, my jack started leaking from the bottom of the lift piston while we were away, creeping down faster than I could pump it up and I had to buy a replacement, very nearly threw the original away in Newman but thought better of it. I'll have to give it a go when everything else is cleaned up and put away.