It isn't supposed to look like this!
The buggy has been acting up as of late. The oversized tires I bought for it finally wore out (I guess we've been driving it a bit!) so I ordered a new set with flashy alloy rims. Shortly thereafter, it started making a banging noise coming from the rear. It got worse as the the days progressed and finally one day on the way home, it made the banging noise and then a grinding noise - but that went away.
It sounded like it was coming from the left rear, although Mark swears it was coming from the front. What was wrong? Was the differential blowing out? The brake shoes dragging? A bad wheel bearing?
It can't be the wheel bearing, right? Because when those go bad, they make a roaring noise and this was a banging and popping kind of noise and it was only occasionally. Well, Mark took the buggy to visit some potters and it went bang and then sounded like the brakes were dragging. So I went to pick up the buggy and when I put it in reverse, the dragging noise stopped.
All the way home it would bang and pop and sometimes the dragging would start. I would put it in reverse and then go forward and it was fine - for a while. Maybe a rock in the brake drum? Brake shoes dragging? Oh, well, time to take it apart and find out.
As in any automotive project, jacking it up is half the battle.
The first problem is that the buggy is 30 years old and as far as I can tell, the brake drums have never been off it. The dust cap was fused by corrosion to the cap receiver. After struggling with it for an hour, I finally cut it off with an angle grinder. Crude, but effective.
The service manual states that the dust cap is optional. If you have a wheel with a center cap (as we do) then the dust cap is redundant. Besides, the bearing is sealed, so no dust can get in anyway. By the way, service manuals are essential if you want to work on something, but they are getting harder to come by these days. When we bought our 1995 F150, Ford sent us a postcard asking whether we wanted to buy service manuals (GM used to do this, too) and for a few bucks, you could have all the manuals (which took up half a shelf) and had all possible repairs laid out in excruciating detail.
Having a service manual with diagrams so you know what you are dealing with, is essential!
Today? They want to keep that data proprietary - so you have to go to the dealer for service. Ford will offer to sell you the owner's manual, and that's about it. There are manuals available online, from eBay for example, as downloadable pdfs or even USB thumb drives. How times have changed. I miss the grease-stained pages of my F150 manual. Sometimes it is nice to hold something in your hands. And how can you turn the pages on a pad device with grease and dirt on your hands? On the other hand, the pdf file is only a few bucks.
Anyway, once I get the castle nut off (140 ft-lbs of torque!) I find.... nothing at first. The brakes look fine and the drum isn't scored. It isn't until I clean it up with acetone that I notice the outside edge of the brake drum is scored and the bearing seal is shot. The manual calls for using as slide-hammer to remove the bearing axle assembly. You know what? I hate slide hammers. Yea, I own one, but it never does jack shit. I try it and the bearing won't budge. I finally McGuyver up a rig using a gear puller and two bolts, that I put on the axle shaft. By tightening the castle nut, the bearing slowly pulls out.. This is better than sex!
And once out and the layers of grease cleaned off, I see the problem. Nearly 1/3 of the balls are missing, the ball cage is wadded up (what is left of it) and chunks 'o balls are mashed in the grease. The banging noise was the balls breaking up as chunks of broken ball wedged into the "good" balls. Eventually enough balls were busted (sorry!) that the axle moved upward, allowing the brake drum to rub on the backing plate. Let's hope the axle flexing like this didn't damage the differential spider gears. Oh well.
Off to eBay and the brake kit - with all the fixin's - is like $30. The bearing set (both sides) with seals and new circlips, is only $25. I was able to get the bearing off the axle shaft with my gear puller (using it the correct way this time) but I may have to drop by NAPA to have them press the new bearing onto the axle shaft.
It gets tricky with bearings. If you put too much load on them or hammer them while installing, they will brinnell the races. I mentioned before how Rockwell hardness testing is used to measure hardness of metal by using a diamond point and seeing how far it goes into a piece of metal with a predetermined amount of pressure. Brinnell testing is sort of the same thing, but uses a hard ball as the penetrating point. If you bang on a bearing or overload it statically, the balls will make little dents in the races and you will "feel" it if you spin the bearing in your hands. Eventually, that bearing will fail prematurely as these little dents slowly tear apart the balls.
So you have to be careful installing bearings like this. They are a press fit and as such have to be carefully installed, and not hammered or over pressured. One technique is to put the smaller of the two parts in the freezer or other cold place, so as to allow it to contract, while heating carefully (with a hair dryer, not a torch!) the other part. Sometimes they will just slip together this way and then "grow" together as the temperature equalizes. I doubt that would work for a bearing, though.
So what holds this all together? Massive bolts or something? Not exactly. It is fascinating how flimsy the construction of cars are, in some regards. This axle assembly is not unlike that of many car, including the Jeep (rear axle) or my old 1974 Maverick. In the case of this golf cart, two circlips hold the bearing in place (that and the press fit) and that is all that prevents the axle from just working its way out of the axle housing.
Some cars are far worse. Older GM rear wheel drive cars didn't have sealed bearings like this, but used roller bearings which rode in the same fluid as the differential. The axle itself was held in place by a tiny clip on the inside end, where it protruded from one of the spider gears. If this clip fell off or wore out, well, the entire axle on one side would "walk" outward. You may have seen an old GM pickup truck or van parked by the side of the road with the wheel sticking out this way. Kind of weird that the only thing holding the axle in place is a tiny metal clip about the size of a silver dollar and costing sixty-nine cents.
That is one advantage of rear disc brakes - if the axle goes astray, the brake pads will at least hold it in place for you!
But I digress.
Anyway, the buggy is out of action until the parts arrive and I get to work on it. I have the parts to do both sides and will take this opportunity to drop the differential pan (on golf cart, they are on the bottom) and look for any metal chunks or debris, and change the differential fluid. And yes, I will do the other side as well - at least the brakes. I hate to mess with the bearing on that side, if it isn't broken. Then again, after 30 years, odds are, it's about to - right?
30 years - you'd think they'd make 'em last longer than that! Quite frankly, golf carts are one of the most over-engineered products out there. They are built to last the ages, but most golf courses swap them out when the batteries need replacement (usually they lease them). And that's why you see so many used golf carts for sale. Golf courses don't want them, so that leaves only the recreational users.
And if they last 30 years or more - we will eventually drown in a sea of used golf carts!
