Steering: O-Ring in Saginaw Power Steering hose

[Charlie D]

For the second time in a few months I am trying to eliminate a leak in the Saginaw Power Steering hose. The culprit is the o-ring that is supposed to seal the smaller, lower hose going into the back of the pump itself. The last time I had it out I tried unsuccessfully to find one a little larger to hopefully get the sealing back to stop the leak. The photo shows the fitting and the o-ring that is not working.

The o-ring in the larger, top hose works well. I can feel the drag (contact) of the o-ring about 1 to 2 full turns prior to the fitting being tight. The lower o-ring appears to make contact just before the fitting is tight. Evidently not enough squeeze to prevent the fluid from leaking out. It is a very slow leak but I feel it should not leak at all if I can get the appropriate size o-ring. I have given some thought to trying to find a fiber flat washer to go on before the o-ring and thus getting a better squeeze that way.

The photo shows the dimensions of the fitting area the o-ring attaches to as well as the dimensions of the o-ring itself. If anyone has an o-ring that is fatter in diameter than the .100 that this ring is or maybe knows of someone who repairs the Saginaw system and has an o-ring that does what I am trying to get done I'd appreciate it. I am going to research the web to see if an o-ring that may be a better fit can be found. I am afraid if I find one, the vendor may want to sell them in lots of 100 or so. I do not need 99 unused o-rings laying around.

Thank you for any help or ideas you can come up with.

Charlie D.

[bensherb]

I don't know how it fits on the tube (I have bendix) but you might try something like this: Roughly .080 X .375 ID should be about .565 OD

[DieselJim]

Try the parts counter at a heavy truck shop. They usually have a drawer of progressive o ring sizes.

[bezhawk]

Are you sure it is the "O" ring, and not the cone seat on the other side of the fitting? Ty chucking the fitting in a lathe, or drill, and dress the taper smooth. If that won't work, there are copper conical seats available for flare fittings that will work.

https://www.grainger.com/product/38N882&AL!2966!3!166596746330!!!g!104634496677!?gclid=CIHRodrc79QCFQY0aQod9BkPZQ&cm_mmc=PPC:+Google+PLA?campaignid=719344945&s_kwcid=AL!2966!3!166596746330!!!!104634496677!&ef_id=WVfQcQAAAD47ujzD:20170704132350:s

[52-fan]

Try the parts counter at a heavy truck shop. They usually have a drawer of progressive o ring sizes.

True, when I worked in a trucking company parts department I kept all sorts of O-rings. The catalogs had many sizes, you can actually select i.d., o.d., and thickness, in several different materials. We were not set up to sell parts, but if someone came in with a need, we would figure out a price and send them to the front office.

[GrumpyOne]

For the second time in a few months I am trying to eliminate a leak in the Saginaw Power Steering hose. The culprit is the o-ring that is supposed to seal the smaller, lower hose going into the back of the pump itself. The last time I had it out I tried unsuccessfully to find one a little larger to hopefully get the sealing back to stop the leak. The photo shows the fitting and the o-ring that is not working.

The o-ring in the larger, top hose works well. I can feel the drag (contact) of the o-ring about 1 to 2 full turns prior to the fitting being tight. The lower o-ring appears to make contact just before the fitting is tight. Evidently not enough squeeze to prevent the fluid from leaking out. It is a very slow leak but I feel it should not leak at all if I can get the appropriate size o-ring. I have given some thought to trying to find a fiber flat washer to go on before the o-ring and thus getting a better squeeze that way.

The photo shows the dimensions of the fitting area the o-ring attaches to as well as the dimensions of the o-ring itself. If anyone has an o-ring that is fatter in diameter than the .100 that this ring is or maybe knows of someone who repairs the Saginaw system and has an o-ring that does what I am trying to get done I'd appreciate it. I am going to research the web to see if an o-ring that may be a better fit can be found. I am afraid if I find one, the vendor may want to sell them in lots of 100 or so. I do not need 99 unused o-rings laying around.

Thank you for any help or ideas you can come up with.

Charlie D.

[ATTACH=CONFIG]65293[/ATTACH]

Often, the failure for "O" rings to seal are seat flaws. Sealing effectiveness increases with pressure and if there is a flaw, (even a minor scratch), in the seating area, the seal will fail.

As an example, a diving tank has an "O" ring seal between the tank and regulator which is subjected to nearly 3,000 PSI yet the seal is set by a thumb screw that only needs to be hand tightened...

[Charlie D]

I really appreciate your suggestions and feedback. Brad, I think the leak is at the o-ring side of the fitting. I do not see any leaking on the fitting itself but rather it is running down the back side of the power steering pump. Thank you for letting me and anyone else interested know that there are those other type seals available.

James, I will check for burrs on the surface area of where the o-ring goes. I did some research concerning o-rings. I found a table of standard sized o-rings which was listed as AS568 with a dash and then a number. It appears the o-ring that is being used now is an AS568-112 (1/2 x 11/16 x 3/32 (.103) cross section. I ordered a few of the next size up AS568-206 (1/2 x ¾ x 1/8 (.139). I will see if the extra .036 of thickness will put a better squeeze on the seal area.

Once again, thank you!

Charlie D.

[Corley]

There are 'merican size 'O' rings, and their are Metric sizes of 'O' rings. Stop off at HF and pick up an assortment of each, for about $5 each box full of various sizes. Then, if those won't work, check into the HVAC 'O' rings, for even more sizes (and better quality). Again, an assortment of each is nice to have at home.

[Charlie D]

The next size up appears to have done it.

The thicker o-ring started to make contact with about 1 1/2 threads to go and appears to have put a good seal on the fitting.

Charlie D.

[52-fan]

Glad it worked. You are one step closer to driving that car.