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Overhauling counterbalance and rebuild thread: full parts list and procedures


Feb 8, 2021
Top post has the parts list. Procedure and pictures in the comments.

Hydraulic seals from herculesus.com:

I ordered different styles and two of each in case I messed one of them up or changed my mind. I decided on the ones with the "square o-ring" style:


Recharging tools:

1. "High-Pressure Inflating Connection Schrader 1/8 In NPT Male, Manufactured by:Amflo, Toolsource #:106074, Manufacturers Part #:556, Also Known As:AM556"
Pegasus Auto Racing Supplies.

2. "JGB Enterprises-A171-1004-0048 JGB-JFlex Hydraulic Hose, 1/4"x4', Male NPT x Male NPT Connection, 1-Wire, 3265 psi, Black"

3. Smallest welding Argon/Nitrogen bottle from any welding supply shop. I used Argon.

4. "Legines NPT Reducing Coupling Brass 1/4" Female x 1/8" Female, Hex Reducer Coupler Adapter Pipe Fitting 1200psi (Pack of 2)"

Refilling with oil:

1. Measuring cup
2. Vinyl tube to syphon the oil in/out.
3. Mobile DTE25, ISO 46: https://www.amazon.com/gp/product/B071VDRP8Q

Hydraulic hose from DiscountHydraulicHose.com:

R1-04-ASB | 1/4" SAE 100R1AT Hydraulic Hose Assembly
both fittings: MPX-04-04
90 inches total length for 1996 VF-Oe

(You will appreciate the swivel fittings -- these make assembly much easier.)

Manifold block (stainless cube thing):

1. ASHCROFT "Gauge, Pressure, 0 to 1000 psi, 304 SS" Zoro #: G8516444 Mfr #: 251009SW02L1000#
Ashcroft 251009SW02L1000# $81.64 Gauge, Pressure, 0 to 1000 psi, 304 SS | Zoro.com

(Note that this is a 1% accurate gauge. There is no 1% gauge under 2½ inches diameter.)

2. Haas SWITCH, PRESSURE 750 PSI 8975

3. "Fitting UNF 7/16-20 ORB-04 Female to Pipe 1/4� NPT Male Gauge Adapter"

You need to machine the UNF adaptor on a small Lathe as per instructions in the comments.

Blocking the head:

8" charlotte coupling, for example https://www.pvcfittingsonline.com/429-080-8-schedule-40-pvc-coupling.html

Misc Consumables:

1. Loctite 1265769 Pipe Sealant.
2. JB Weld 2-part
3. zip ties
4. cotter pins
5. Permatex 56521 thread seal.
6. 3" hole saw for metal


Feb 8, 2021

Removal of the hydraulic cylinder and reservoir bottle is described in the service manual.

You can use the Charlotte/PVC adaptor to block the head since it is only 10-20 bucks. It is bad to put pressure on the spindle bearings.

To remove the reservoir bottle do as follows:

1. Remove one screw from the top right of the reservoir shroud and replace without its washer.
2. Remove the remaining three screws. The shroud will swing anti-clockwise a little.
3. Lift the shroud over the last screw.

Draining / Refilling:

The 4' hydraulic hose doubles as a drainage tool. The service manual specifies the amount of refill fluid you will need. I was able to refill the precise amount by using a clear vinyl tube that I was able to force down the 1/4" open hole in the top of the reservoir after removing the 90" hose. I used syphoning. It took a whole day to drain 2 quarts of fluid down the vinyl tybe into the reservoir.

( objectivelyspoken.com/uploads/refill.jpg )

Dissassembling the hydraulic cylinder+piston

To remove the nuts at either end is very difficult if they have been in there for 20 years. I made this tool below and used a deep socket and an impact wrench to remove the nuts without damage. There is pretty much no other way to get these off as far as I can tell.

( objectivelyspoken.com/uploads/spanner.jpg )
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Feb 8, 2021
Replacing the piston seals

The seals are very difficult to get off and even more difficult to get back on. I can't even say I have good advise. I blistered my knuckle forcing the seal on and I have extremely strong hands. If you know of a tool, please comment. Here are the different varieties:

( objectivelyspoken.com/uploads/seals.jpg )

Overhauling the manifold cube

The newer style Haas pressure switch has a different thread. For the adaptor:

1. JBWeld it into the manifold cube. It won't seal otherwise because it is not tapered, and,

2. Machine a small recess for the pressure switch's o-ring to fit into the adaptor. I used my lathe to do this. If you don't have a lathe perhaps thread sealer will hold.

I used the white thread-seal for the refill connectors and the red thread-seal for the thread on the dial.

I used a hole saw to cut a recess in the shroud:

( objectivelyspoken.com/uploads/dial.jpg )

The adaptor needs a small internal chamfer machined to accommodate the o-ring. Here it is prior to machining:
( objectivelyspoken.com/uploads/adaptor.jpg )


Feb 8, 2021
Some other tips:

I have a suspicion that the piston can trap some air which leaks out over time. This can result in a slight drop in pressure over the first few days. Not really sure. There do not seem to be any fluid leaks for me.

The pressure in the reservoir seems to vary about 1 psi per degree Fahrenheit (very roughly). So check the room temperature before you assume that there is a leak.