View Full Version : Wheel Bearing Seals

08-13-2006, 10:37 AM
I've been reading about the wheel bearing seals...the felt ones...that are too thick. I'm getting ready to finish up the front end and will be putting the rotors on soon. So, how much has to be shaved off of these puppies?? Also, excuse my ignorance, but exactly how are these seals oriented?? Does the felt section go toward the back of the spindle, or does the felt face the wheel bearing??

08-13-2006, 11:52 AM
I do not know which TR you have but if it is a TR3-6 use the Spitfire front seals which are thinner. I install the bearings without the seals and mark the nut. Then I install the seal.The seal retainer goes in first and then the felt rides against the spindle housing.

Alan T

08-13-2006, 03:50 PM

I don't have easy access to either old or new seals right now, so am going by memory with these dimensions. It was pretty obvious to me that the seal was way too thick, since it stuck out from the rear of the hub by about 1/8". If the seals you have are roughly 1/8" thick felt before installing them, they probably don't need any trimming. Last set I installed on my TR4 were appprox. 1/4" thick as they were received from the supplier. I used a single edge razor blade to trim them down horizontally to about half that thickness before installing. That was closer to the original size seal.

The metal backing (the part that presses into the hub) made trimming pretty easy, it can act as a guide for the work with the razor blade. It also might help to test fit the seals and their backing into the hub (careful removal is a bit tricky, but can be done when the hub is off the car and has no bearings or gobs of grease in it). The felt seal should just barely stand proud of the hub, to rub very slightly against the polished area on the vertical link assembly. Be sure the metal seal backing is fully seated in the hub, so that the metal rim can't rub against the v-link.

I believe the felt seals are best soaked in oil overnight, before final installation. Seems some come as a separate piece and others already glued to the metal backing plate. If separate, I'd use some Permatex gasket seal (hardening type) or similar to glue them to the metal backing plate before soaking in oil. ISTR it's also easier to trim them with a razor blade after they have been glued to the metal backing, if the felt is separate.

I don't know if Spitfire seals would work or not, or if they are made the proper thickness. All the problem/thick seals I've seen fit TR2 through TR6. I don't have a Spitfire or it's seals to compare.

Hope this helps (and makes sense!)


08-13-2006, 05:30 PM
Thank you Alan and Alan. It's makes a lot of sense. At least now I understand how they "seal". The ones I have are about 1/4" thick and are glued onto the metal backning. I'll follow your procedure. It should work out fine.

Thanks again.

08-14-2006, 02:22 AM
the wheel bearing seals...the felt ones...that are too thick

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I am not so sure about this. The idea is for the felt to be mashed in and create a seal. If you remove nearly 1/2 of the felt, the long term durability / ability of the felt to properly seal will be affected.

IMHO, a better method is to put the hub back on, with the full felt seal and watch it (movement of the hub, brake disk) with an indicator to find out when the felt seal is fully compressed (the hub will stop moving as the nut is tightented)

The whole issue of cutting off the felt began when it was pointed out that the manual says to check the bearing pre load by tightening the wheel nut until the hub begins to be difficult to turn and then back off the nut. With a new felt seal however, it is very difficult to determine when the SEAL is causing friction or when the wheel bearing in fact is preloaded.
Wheel bearings which are not preloaded will very rapidly self destruct (as someone here discovered). Therefore, it is important to ensure that there is a small load on the bearing.
An indicator will not be affected by this problem.

Now that the back end of my Herald is almost reassembled, I will be putting the brakes back on the front and take some pictures while I am at it.

08-14-2006, 07:31 AM
The procedure that I've heard (not tried) is to soak the seals in oil, then install the hub and torque the spindle nut to 10'lbs to compress the felt; then back off the nut to the next flat that lines up with the holes for the cotter pin, no more.

Alternatively, use a modern rubber seal Chicago Rawhide CR 13612 type HM21, or Federal Mogul SLS 340823. I got mine from CarQuest.

This is for the TR4-6 front hub, not sure if others are the same size

08-14-2006, 08:52 AM
Thats an old idea-using the CR 13612, I tried it and found that the seal is too thick and rubs/binds on the bearing, they also are too big in diameter and I had to grind down the outside to get them pressed in. Had to pull them out and go back to the felt.

08-14-2006, 03:32 PM

Yes, the issue is that the too-thick seals bind up when you go to set the bearing clearance: "tighten the spindle nut until drag is felt when turning the wheel/hub, then back off one or two flats". When this is done, the too-thick seals are the first thing to drag, long before the bearings are anywhere near where they should be, and engouh that you are fooled into thinking you have the bearing clearance set right. However, as soon as the car goes back on the road all that extra bearing clearance allows a lot of movement, which can cause the front brake caliper pistons to be knocked back into their holes causing the brake pedal to go to the floor next time it's tried, or can even damage the bearings and/or the axle. The felt seal compresses and wears very rapidly and the clearance will become obvious soon, but it might be too late.

Not a lot of seal is needed there, since it's mostly dealing with heavy axle grease that isn't trying all that hard to get out of the hub. The seal just needs to "wipe" the face of the vertical link and, in fact, the thinner, inner edge of the felt that wipes on the very base of the axle probably does most of the actual sealing work. The wider flat area, the part that's being trimmed, might be more of a backup to the primary seal area.