power steering box seals

G

Graham2755

Member
Hi All, I'm fitting new sector arm seals to the power steering box, on my 1972 3500 auto. I've read in the manual about using a seal saver or even masking tape over the drop arm splines to protect the seals as the sector shaft is refitted, but my attempts so far have been unsuccessful. Having no seal saver tool, I just used masking tape, but it just caught on the seals and wrinkled up. Has anyone done this job successfully, if so how did you get around the problem?
Thanks in advance for any ideas!IMG_20210131_122743.jpgIMG_20210131_144420.jpg
 
Try a single wind of insulating tape, but warm it, and pull it tight when applying, and have a little overlap the leading edge of the spline so you can fold it over the edge.
 
If a seal save sleeve is not available I always prefer to use a piece plastic polyester shim material, either 2 or 4 thou thickness. The problem with tape or cling film is that if a small piece tears off and becomes trapped in the seal without notice, then you going to have a leak again. All these methods work well with standard rotary shaft seal, however the main seal in the power steering box is under pressure. So the seal used is a polyurethane lip seal like those that you would find in a hydraulic ram as a rod seal. The lip of the seal is very stiff and the radial clearance is very close to the shaft, so not much space for any tape.
Although a seal installer tool is always good practic, I have installed many sector shafts like this without any aids, just ensure that there are no sharp edges on the shaft and spline. A few minutes with a wire wheel will soon burnish the surface, grease the spline and shaft well and install through the bearing. When the spline reaches the seal the shaft is already centralised by the bearing reducing the risk of hard contact with the seal and damage. The polyurethane seals are very tough and resistant to cuts, the spline is slightly smaller then the seal journal diameter so never had any problems.

Looking at the picture of the sector shaft I would be more concerned with the condition of the seal journal, it is not clear from the picture but this diameter must be clean and a smooth finish, no grooves formed from the old seal. Any damage to this diameter in the area that the seal works will result in a leak later.
 
Thanks, it is encouraging to hear it can be done without tape or film, I had concerns about what might be left behind. Hadn't thought of de-burring the splined area either.
The sector shaft is marked where the seals ran, but I'm hoping the ring of pits lay between the pressure seal and the outer dust seal, where the backup washer is so I'll get away with it.
Just got to figure a way of bench testing it now, don't want to go to the hassle of getting it in the car, then putting the engine back in only to find out at the last minute that it is still leaking!
 
We always pre-test with compressed air to check for external leaks of seals, safer for the test rig operator, no surprising seal failures at high pressures! We have high tech pressure decay systems for during this but there are low tech ways.
If you have an air compressor, tee together the supply and return ports of the steering box to the compressor line, ideally with an on/off valve. We normally test at high pressure 80-90 psi and low pressure 15-20 psi. The reason being that many hydraulic seals will be leak proof at the high pressure as the pressure activates the lip of the seal. However the same seal may not hold a static head of oil because poor surface finish or distortion for example. Test the unit in a water bath and look for the bubbles.
If the seal journal is too badly damaged, this can be recovered by having the journal ground undersize, hard chrome plated and reground back to standard size. There are companies around that will do this work for you.
 
I am about to undertake the rebuild of the power steering box from my 1970 3500S. I had hypothesized that I might put a wiring shrink wrap tube over the splines and then shrink it very tight with the heat gun. After the seals were in, the shrink wrap could be cut away. And of course lube the shrink wrap with PS fluid. Has anyone tried this?

Also, does anyone know what size of spline socket fits the spline shaft which connects to the steering wheel?

Finally, is it necessary to warm the Teflon seal with boiling water before sliding it on? I understand that after it is in place, you can coax it back to size, by wrapping it with saran wrap and then constricting that with a hose clamp?
Keith Hennessee San Antonio, Texas
 
Just a word to all with PAS issues. If the shaft is out of spec or corroded, then you can't simply can't rebuild the box with new seals. It needs to be machined and chromed to the correct diameter. Hats off if you can do that at home.
 
PeterZRH said:
Just a word to all with PAS issues. If the shaft is out of spec or corroded, then you can't simply can't rebuild the box with new seals. It needs to be machined and chromed to the correct diameter. Hats off if you can do that at home.
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I will inspect it carefully, and check the diameter with a micrometer. Thank you for the warning. Does anyone know if there were other makes that used the same steering box?

Keith Hennessee
 
Burmann I believe. I found a place in the UK to do it, a commercial vehicle specialist. It's closely related to the first Range Rover Box with a unique casing.
 
PeterZRH said:
Burmann I believe. I found a place in the UK to do it, a commercial vehicle specialist. It's closely related to the first Range Rover Box with a unique casing.
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Thank you again. I will post more with pictures when I remove the box and get it open. I understand that the Pittman arm is often difficult. I plan to soak it in PT Blaster solvent spray and use a Pittman Arm puller. I also have an electric 1/2 inch hammer driver to remove the nut. Any other suggestions?

Keith Hennessee
 
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