Not long after I had reassembled Baby, our 1967 Savanna Beige Sedan, I noticed that the passenger’s rear axle was seeping fluid onto the backing plate. “Rats!” I thought.
And, sighing, I got out the tools and began the task of replacing the axle seal—what else could it be? I had done the “taste test” (not recommended for the weak of stomach). It definitely was not brake fluid. Now, folks, I don’t actually imbibe what I taste—it’s an immediate knowledge and I rinse my mouth of any possible residue. It’s the humble chemist’s unfailing test! Some people get a dab onto the forefinger and by rubbing between forefinger and thumb can sense what type of fluid they are dealing with.
Sure enough…after getting into the bowels of the axle, it was a leaking seal. I fetched a new seal pack from my supplies.
After cleaning things well and making sure that I had not polluted the new brake shoes, I installed the new seal and buckled up the wheel. Done!
But, I’m here to tell you that not long afterwards, I noted that the same wheel was leaking again. Frustration reigned. I called my trusted VW mechanic and cried a bit on his bony shoulder.
Now not all mechanics will reveal their trade secrets. Barry is different. He’s not afraid that I am going to steal his customers. I have no interest in repairing others’ vehicles. So, he spilled his guts. It was so simple that I almost missed it—thought that I hadn’t understood.
But first…a little background.
Through year 1968, VWs have sported a single-piece axle which is connected to the transmission. The axle is encased in a tube which bolts to the transmission housing and to the spring plate structure at the outer–wheel end. Tranny fluid courses at will inside this tube, lubricating the wheel bearing.
Through year 1964, Volkswagen installed a bearing cover onto VWs into which the seal had been pressed into the outer surface. If the seal failed, and ultimately it would wear out, the transmission fluid seepage would exit around the axle and out into the drum. This seepage would transfer to the brake shoes reducing braking power and building a greasy glaze inside the drum and on the shoes.
In order to cope with this eventual seal failure, VW had early developed a complicated set up, including a special rear brake drum and little “spoon-like” troughs which were intended to funnel the seepage away from the brakes and out of the drums. The truth of the matter is, these drums are no longer available. Some, like my VW friend who has a restored 1957 Beetle, are fortunate to have a viable set of rear drums, set up as they were meant to operate. There is a solution to this lack of parts situation–but, that’s for another time and another venue.
Well…let’s fast-forward to 1965. VW decided to amend the situation. Engineers had been at work to solve the problem of seepage, wanting to simplify the mechanics of the matter. And, like most improvements, simplification usually also means cost-cutting. Rather than to install the seal into the outer portion of the bearing cover, they devised a new bearing cover designed to be a self-contained unit. Inside the bearing cover, VW installed a loosely fitting “oil slinger washer”.
This “slinger” actually is loose enough inside the cover that it does just that—it slings about as the axle turns. The hole on the outer surface of the bearing cover, which we see when we remove the drum, is just small enough so that the slinger washer cannot escape. The inner diameter of the washer is just larger than the diameter of the axle itself. The “compartment” in which the slinger works is about 1/4th inch deep—allowing some “slop”.
Now, instead of pressing the seal into the bearing cover from the outside, the seal was pressed into the inner recess, holding the slinger captive. A side note here: New slinger washers are no longer available. My advice to ’67 owners is to have a spare or two. These can be obtained from salvage yards. Remember—the slinger was used from 1965 through 1968. This helps to make supplies of used slingers available. Slingers also were used on vehicles other than Beetles, increasing the chances of finding good used ones.
A small hole, drilled into the bottom of the bearing cover conveyed any seepage out of the bearing cover, through the hole and through a matching hole drilled through the backing plate. Now, any seepage automatically and easily would be conveyed away from the drum and brake shoe surfaces. Ingenious engineering!
Here’s what to do when servicing a rear axle. I’m not going to cover the entire procedure—just the bearing cover and installation of the slinger washer and the seal and its installation onto the axle prior to bolting the cover onto the housing.
Clean the bearing cover well. Leave no debris inside. I also clean the outside assiduously! I want no dirt put back into the workings. Clean the weep hole in the backing plate. We want any subsequent seepage to have a clear path out of the wheel.
Now, it’s time to install that slinger washer. Just drop it into the recess. No fuss—no muss.
Next, install the seal. If you have a seal installing tool, or a press, all the better. Otherwise, you can use a ball peen hammer and a block of smooth metal or even a block of wood. You may need to go round and round using a flat punch to finally seat the seal. Look from the outer side to see into the cover to be sure that the seal has seated all the way around.
At this point, install the components onto the housing and axle. Note: the thin metal washer which comes in the new seal packet is NOT the oil slinger. It is a thin, tinned piece of metal which serves an entirely distinct purpose. (A Tip: If this thin washer in your packet has sharp edges from the factory stamping, use a small file to smooth those edges)
Install everything in reverse order (hopefully, you kept a record of how things were installed before you uninstalled them). But, wait….
Before installing the wide, outer spacer, we want to use our new-found knowledge. This is the “trick” which we want to employ.
We are going to install the spacer into the bearing cover BEFORE we install the cover. By carefully pushing this spacer into the seal, we are going to avoid pinching the lip of the seal or otherwise damaging it when the cover is slipped over the axle. You may lightly oil or grease the outer diameter of the spacer so that it will easily push into the seal opening. Be sure to have the beveled end of the spacer pointing towards the bearing—that’s where the small O-ring will seat.
Now…carefully push the bearing cover, spacer and all, onto the axle. It will slide on smoothly without ever touching the lip of the seal. Bolt up the bearing cover.
It’s time to install the drum and the axle nut. Hand-tighten the nut—then use a tool to further seat the nut.
Lower the car and finalize the torqueing of that axle nut—to at least 217 foot pounds. Do NOT attempt to torque the axle nut with the car on stands. The torqueing process will throw the car off the stands! And remember, a poorly torqued axle nut will result in tranny oil seepage—the least of your worries. It will also allow the drum to wobble on the axle. This eventually allows the hardened steel axle to eat away the soft, cast iron drum splines resulting in a “spun hub”. Worse—the nut could loosen sufficiently to allow the entire wheel to fly off the axle. So do your best work here.
When the nut has been torqued, install a new cotter key. If you cannot find the cotter key opening, do not loosen the nut to find the hole. Instead, further torque the nut until the cotter key hole appears.
Some time after I learned of this maneuver, a VW friend called me—frustration evident in his voice. He had installed seals 3 times on his rear axles and each had leaked in short order. I explained the safety procedure. The next time we talked, he told me that he’d had no further problems with leaking seals.
Knowledge is a great thing when properly directed!
Photography: Neva Salser