Reference: C8A HUP grease seals

[Malcolm Towrie]

I am involved in restoring a HUP and I found this thread which I think answers one of of our questions: we have pulled the outer ends of the front axle to replace the three seals and found the axle oil seals measure at 3.060" od by 1.490" id, which I asume is a nominal 3 1/16" od by 1 1/2 id seal. This size is unobtainable now, so, if I understand Bob's post, we need to machine a ring to press into the the axle housing to reduce the size of the seal od to something obtainable?

We can reuse the grease seal that seals the egg cup, it's not in bad shape, but the large grease seal stopping grease from the hub bearings getting into the drums is shot. Are these obtainable? Or is sleeving also required?

Malcolm

[David Herbert]

Is it possible that these seals are metric ? 78mm OD and 38mm ID ?

David

[Malcolm Towrie]

Good suggestion, Dave. I searched for those dimensions but didn't find anything exact, although I got closer than I did with the imperial sizes, 35x78. This size gives an extra 1/16" per side compression on the seal lip which is a lot, but considering the relatively low speed and the extremely low usage, it might work.
Malcolm

[Bob Carriere]

Your best bet is to take the old seals,bearings etc and visit a General Bearing services....aka GBS..... they will measure the parts accurately and search world wide for the item....... one seal inside the front axle could not be found with the proper ID and OD...so we bought the one with the good ID size and had a machine shop turn an adapter in aluminum to fill the gap between the axle tube and the seals...... once pinned in place they never leaked....

They search by size and not necessarily by part number....typically they will find 2 or 3 sources for often great variation in price and various location.... you pick the cheapest for shipping.

Good Luck.

Bob C

[Malcolm Towrie]

Thanks for the response, Bob. I find the SKF/Chigaco Rawhide web site search below the best out there. I figure they make most of the seal sizes worldwide!

https://www.skfextranet.com/crsealsf...35X78X8+CRW1+R

And, yes, I recently went through the exercise of buying oil seals for a Centurion gearbox and final drive. Like you say, our supplier couldn't get the sizes needed because the seal dimensions made 70 years ago are not available today, so we ended up buying the right shaft size and machining spacers to adapt the seal ODs to the housing bores. Looks like we'll be doing the same for some of these HUP seals.
Malcolm

[Hanno Spoelstra]

Malcolm, I have merged your posting and its replies into this separate thread as more people must be running into this problem.

I think Hendrik van Oorspronk had the same problem, but I don't know how he solved it. I don't have the answer either, so let's hope that whoever finds a solution posts it here.

Indeed the SKF CR Seals website is an excellent resource to look up seals: https://www.skfextranet.com/crsealsfinder/
(PS: SKF bought Chicago Rawhide many years ago but recently decided to reuse the CR brand as it still had an exellent name in the world of seals).

[Malcolm Towrie]

Ok, Hanno.
I've found out some more info.
I'm going to trial fit a metric seal as suggested by David. The part number is 35X78X8 CRW1 R. It'll be a tight fit in the bore (0.010" diametral interference) and it's tight on the shaft (at least 1/16" interference) but it might work for this low speed, rarely driven application. I'll get one and see how it feels.

I suspect this axle seal has very little to do except when going off road. It looks like the diff oil level is below the bottom of the axle, so the seal will rarely see oil when street driving. This might be a good reason NOT to use the above seal, as without any lubrication, the rubber lip on the seal may rub hard and wear quickly.

The area on both axles where the seal rides is very corroded, another reason I think this seal sees little oil, so I was considering installing SKF speedi-sleeves, part number 99147, to bring it back to good condition. These are very thin sleeves that's can be pressed onto the sealing part of the shaft to cover the damaged area and still allow use of the original-sized seal.

The large grease seal on this C8A HUP is 6.25" x 5" so I'll be getting the SKF 49998 seal. The Motion Industries web site, which is also a good resource, says the Timken 416865 is also an option.

The pinion seal bore and shaft diameter are 3.060 x 2.250, so an SKF 22382 should fit.

I'll update on how I get on.

Malcolm

[Lynn Eades]

Malcolm, if the seal happens to be double lipped you could put some grease between the lips.

[David Herbert]

Malcolm,
You say that the seal contact area on both axles is very corroded. I think that it is pointless putting new seals in as they won't stand a chance of doing any sealing. Is it possible to precision cylindrical grind the sealing surface which will help the size mismatch and give the seals a chance to seal against a smooth surface. As long as this will not be the smallest diameter area of the shaft it shouldn't affect the strength. You just need an engineering shop with a big enough capacity cylindrical grinder to do the job.

[Malcolm Towrie]

Dave, I think I have the solution.
SKF make very neat sleeves specifically to restore shaft damage under lip seals. If I install one of these Speedi-sleeves, part number 99147 on each axle shaft, that will bring the diameter under the seal up to 1.512" since the shaft was originally 1.490" and a speedi-sleeve is 0.011" thick.
Luckily, I found some 3.25" x 2.490" mechanical tubing at the museum, so I can machine a spacer ring with an od of 3 1/16" and an id of 2.250". This will press fit into the existing bore in the axle and then we can press fit SKF seal number 15141 into the spacer and that should seal well on the speedi-sleeve.

I understand this is not an easy option for most but I'm afraid that's what it seems to take to replace this seal. Total cost of this option is $10 for the seal, $50 for the speedi-sleeve, and maybe $100 for getting a shop to make the spacer ring. Not a cheap fix!
Malcolm
PS As I said above, I'm not convinced this seal needs to seal for street driving. So to pay for the full fix may be a waste of money. After all, our HUP had the original leather seal, an extremely corroded axle shaft land under the seal, yet no obvious leakage of diff oil into the eggshell. It was grease that leaked big time into the drum. The big grease seal is the critical one.

[Malcolm Towrie]

I've replaced the three types of seals in the HUP front axle.

For the axle oil seals (the ones closest to the diff), I used SKF part number 38x65x10 HMS5 RG.
This seal fits snugly on the 1.490" diameter axle, but to make them fit in the axle tube ID OF 3.060" I had to machine two rings with 3.063" OD X 2.559" ID. This gives a nice press fit of the ring into the axle tube bore, and a nice press fit of the seal into the ID.

For the large grease seals installed in each drum/hub assembly, I used SKF part 49998. These were also a very nice fit in the bore and on the hub.

For the pinion seal, SKF 22382 was a good fit.

Malcolm

[Hanno Spoelstra]

Malcolm, good to hear you got it sorted and posted the details here for future reference

[Hanno Spoelstra]

Jordan Baker posted this photo of the modern inner axle seal on his C15A.

Posted here so we can see what an inner axle seal looks like