Gentlemen (and any Ladies) I have a Hallibrand quick change diff on my 1953 Chevy pickup that I'm restoring. This truck is fairly unique with a Vertex magneto, McCulloch supercharger (from a Studebaker Golden Hawk), four speed Saginaw transmission (from a 1967 Camaro) with a T & F shifter, along with the quick change diff. I bought the car from a buddy who had purchased from the estate of the guy who was originally building it. I've been working on for two years and am nearing the finish line. Right now the engine is being rebuilt and while it and the drive shaft are out, I continue to see drips of fluid coming from the yoke side of the unit. See photos below - See photo below, the drip seems to be coming from between the back plate and the diff unit itself. There isn't any gasket visible and wonder if it normal for it just to be metal on metal, or is there possibly some internal o-ring. I"d like to dis***emble the yoke from unit via the center bolt (does it just come off or is it pressed on?). If I remove the six nuts around the perimeter will that section come off? What about the circular plate behind the yoke? Just trying to ask questions since I don't have an ***embly manual or anything for this unit. Thanks in advance for any ***istance. Bob
I ventured further and removed the yoke (easily) and then the plate attached by six nuts. This is what I found. No sign of an o-ring, but the gasket/seal in the center of the plate might be leaking and that star shape doesn't appear to be a gasket at all. . The diff unit itself is leaking fluid and I don't know if that's normal.
The question is -> was it leaking between the seal plate and the casting (which tells me the gasket is bad and/or the plate is warped or both. Or was it leaking out past the seal? My guess is that it is leaking via the gasket and/or the lower stud. I'd check the seal out carefully and probably replace it. Also, you'll need a new gasket. Clean all the old silicone sealer off the plate as well.
Also, check and see if that lower stud could be leaking. I can't remember if that is a "through hole" to the interior of the casting. If so, maybe put some "stud sealer" around all the studs (removing them first).
Bob, There was no gasket on the original Halibrands. But you can make one up. It is amazing how that gear oil will migrate past the bearings and even between the splines on the front yoke. Yours doesn't seem like it is leaking between the splines, though. Also, if the front bearing is sloppy, you will have a heck of a time in getting it dried up. There are speedy sleeves available if the leak is between the O.D. of the yoke and the actual seal. Here is what I would try in order to stop that leak. Drain the gear oil out of your unit. Clean the surfaces thoroughly of all traces of oil. Clean the Splines on the input shaft and yoke. Put a thin coat of black RTV sealer on the face of the seal plate. Bea sure to go around the bearing O.D. Put the seal plate on and snug it up. Put more RTV on the splines of the input shaft. Install the yoke and put more RTV on the backside of the washer. If you want to go to the extra work, you can remove the rear cover and change gears. Tap the lower shaft forward to remove the front bearing. You can either put RTV or Green Loc***e on the outer surface of the front bearing. Remember to replace the gear oil! One last thing, be sure that the unit is vented. It doesn't take much, but if there is no path for the pressure to get out, it WILL find a way out!
Where should I insure that the unit is vented? Is there a vent already in the unit somewhere that I need to look for. BTW, today I finally noticed the model number, it is 201.
I used a vented bolt that I bought from Winters for my Champ QC. Drilling an axle is an option, I did that recently on a 9" ford rear end. I slipped out the axle, shoved an oily rag past the drill spot, lubed up the bit with plenty of grease to catch the chips, drilled it, pulled the rag out that caught the rest of the chips, tapped and threaded a vent. All diffs must have a vent or they will force the lube past the seals.
No, Halibrand didn’t vent them. But maybe the subsequent builders did. They originally vented through the torquetube and transmission, but the open drive eliminated that.
That notch in the gasket was for a drain back hole in the original Ford application, it goes nowhere now. I would make a new round gasket not star shape, without the notch in it , to get a better seal.
When I had my 9 inch set up the guy who set it up said to not use a gasket, that the gear oil will migrate through the paper. He suggested to just use a silicone seal as Mr Gearhead has suggested
Another way to vent is to put a threaded hole in where Bandit Billy did or another place high up. With a hose barb and a length of hose you can fill from outside. In our race cars we have a funnel in the trunk area and can dump the fluid in and let gravity do it's job. Put a rag loosely in the funnel. The trunk lid keeps the rag from falling out. The vent feeds directly into the gear change cavity.
As usual, thanks to all that have responded - I really appreciate all the knowledge. I spoke with Ryan at HotRodWorks.com yesterday and he reiterated almost everything you guys have p***ed on, very helpful. I post some pics after I finish cleaning everything up and re***emble. I decided to replace the seal that is on the round plate that the yoke is inserted. Once they arrive, I'll put it all back together. I've been debating on replacing the bearing that is at the back of the unit that the splined shaft come through. It sounds like I can remove that shaft an then pull that bearing and replace. The debate is 1) how easily the shaft will be removed 2) how easily I can pull the bearing, 3) how readily I can find that bearing, and 4) whether it needs to be done at all.
To be very honest, I have not had great luck with o-rings. I find it better to fill the groove with RTV.
I don't really know anyone that could put an o-ring groove in the plate any how. Might be a great idea but I'm going with the RTV.
While I'm waiting on the seals, what weight and/or brand of gear oil do you all use on the Halibrand quick change?
Valvoline Dura Blend 80/90, as recommended by Halibrand. @77xmatt stated: "Be careful if your quick change is using sealed bearings, you will need to fill the rear gear area separate from the front ring/pinion area! If your bearings are the older style open bearings then you can do as advised. Mine has sealed and when I take the rear cover off to mess with the QC gears it only drains the rear compartment. That would be an expensive mistake…"
For gear lube consider RedLine Shockproof. Its a synthetic and will run a tad bit cooler than regular gear oil.
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