How to size hydraulic seal

[fbody_mike]

Ok, so I have decided I am going to try to rebuild my 85 gs550e's P.D.F module. It the click adjuster that attaches to the bottom of the fork leg. So I pulled it apart and was able to find two seals, a large o-ring and a U-cup seal. From what I can tell, in the industry they call them wiper seals or rod seals. Since this is not something that Suzuki ever listed I am sort of on my own. But for the most part it is a rod seal in the hydraulic sense, being that it seals a rod with internal fluid pressure, and the rod is one that moves across the seal.

So I did some measuring, and the rod is 15.94mm in diameter, and the cavity that holds the seal is 24.2mm in diameter. So here is the question, how do you pick the seal size? Online, I can find some rod seals that are 16x24x3.5, but I can also find 15x24x3.5 and what seems like random variations of the i.d and o.d. Should I be matching the exact dimension of the hard surfaces, going oversized by a certain percentage? The original seal measures 16x24x3.5, but I have no idea if it has swollen with age or shrank.

[derwood]

bearing supply house, there are many, like this place...https://www.motioncanada.ca/taxonomy...eals/browse/en

[mmattockx]

So I did some measuring, and the rod is 15.94mm in diameter, and the cavity that holds the seal is 24.2mm in diameter. So here is the question, how do you pick the seal size? Online, I can find some rod seals that are 16x24x3.5, but I can also find 15x24x3.5

Seal dimensions are based on nominal sizes, just like bearings. For the numbers you list you will want the 16x24x3.5 seal. I agree with derwood that going to a local bearing supply house with the seal in hand is probably your best bet if you are unsure of what is needed.


Mark

[Steve]

OK, I see you are working on your front suspension and I have to ask, ... what does "P.D.F" stand for? :-K

I have not had adjustable front suspension, so have never heard the term.

.

[fbody_mike]

Posi Damp Forks. Part of the anti dive system when braking. The mid 80s 1150e, gsxr 750 and 550e had them.

[bwringer]

This place called Metric Seals, Inc. is local to me, and they've been helpful for, well, metric seals. Just like it says on the label...

Anyway...

https://www.metricsealsinc.com/

[fbody_mike]

Thanks for the advice guys, I found a local supplier online and ordered up a couple of seals in 16x24x4 mm. Now if all the parts for the front show up by Saturday I can get this done this weekend.