March, 2009: Brakes & CV Joints

I noticed the left rear brake was seeping, and decided to rebuild the rear brakes. Removing the rear wheels, I noticed some slop in the transaxle. Looking closer, I saw a tear in the CV joint boot (never a good sign).

Obvious seeping, time to rebuild the brakes. Uh-oh, the CV joint boot is torn! Remove the half-shafts as a unit. Remove the 10mm socket head cap screws from the transaxle flange, and from the wheel hub. After carefully prying the joints free (two roll pins at each end), the CV joints will compress sufficiently to drop out.

On the bench, I can see the source of the free play. The axle was rattling around in the dry, damaged CV joint. After some research, I was happy to find you can drop in a 930 CV joint directly. Note that some folks have drilled out the roll pins, and fitted a nut-sert so they can attach with 6 bolts instead of four. However, I'm sticking with the factory solution. After all, the car has > 100,000 miles, with no sign of failure in the half-shafts.

On the bench, I was surprised to find that though the remaining 3 boots were intact, only one was in good shape. The remainder were quite dry under the boot, and had noticable free play. The metal end caps just pry off both ends of the CV joint, and you remove the half-shafts by removing the locking rings, and withdrawing. Note the rolled pins. These are not dowel pins, but are very hard, being made of spring steel. The two pictured should be located in the wheel hub, but somehow came out with the CV joint. Perhaps a little thread-locker will keep them in place.

Onto the brakes. I guess they were doing more than seeping. The pads aren't worn, so I'm going to soak them on acetone for a while and see if I can re-use them.

You can see the pistons and the piston seals. I have already purchased a NOS rebuild kit. Installation should be fairly straight forward.

Thank goodness for Jay's parts washer. I could dump the whole load in at once, and get to scubbing. After a couple hours of hard work, everything is squeaky clean. Of course, I'll order brand new M10 x 60 x 1.25 socket head cap screws, with a 12.9 hardness, to put it all back together. I've got to torque those little puppies to 88 lbs/ft!

Here's a look at the new CV joints. I bought the boots from an off-road racing supply shop, who also sold me the lube. They run 1/2 101 Moly CV joint lube, and 1/2 Moly anti-seize in all their machines. They said to dump both tubes into a big plastic bag, and knead to mix. Who am I to argue with success?

I'll try to post more pix when finished.

April, 2009: Brakes & CV Joint Update

OK, a little more discovery. I found that two of my CV-joints had been replaced previously, and two were original. Here's a look at how the rolled pins engaged in the original CV joints. Note the "shoulder" in the holes accepting the pins, to keep them from working themselves loose.

Here's another view of the pin and the shoulder. Note that the replacement 930 CV joints don't have a shoulder to accept a pin. Thus, the pin could, potentially, work itself loose. As stated earlier, one solution offered was to drill out the pins, and use a heli-coil to attach the hubs with six bolts instead of four (more clamping force). The downside is that you don't "precisely" locate the CV joint on the hub, which could cause imbalance at speed. Another downside is you're crossing the line of originality, which is not reversable.

I thought about this, and decided I just needed to make sure the rolled pin wouldn't come loose in the CV joint. Why not just thread the CV joint, and use a setscrew to provide a "stop" for the rolled pin? After some measurements, I determined a 7/16 x 20 tap would fit in the existing holes without drilling. I bought a handful of 7/16 x 20 x 3/4" setscrews, and set about tapping two holes in each CV joint. Note the use of a tapping guide on my mill to really ensure I'm cutting a straight thread.

So, here's the finished product. The rolled pin won't be able to come loose. No irreversable drilling and heli-coil needed on the transaxle hubs or the wheel hubs. I can fine-tune how little clearance to provide between the setscrew and the rolled pin. A little red thread-locker, and Bob's yer uncle!

June, 2009: Oil leak (Valdez)

Time to tackle the grandaddy of oil leals before Monterey. It seems oil is spraying out of the left (driver) side cam chain tensioner. Has been for years, which has kept rust at bay (glass-half-full). The bad news is it sprays oil all over my belts, which continually slip. I suspect the culprit is an O-ring that seals the junction between the tensioner and the head. However, that area is totally blind on the Bora, owing to its location.

The first step is to remove the valve covers and lock down both left-side camshafts. Remember this is a quad-cam V-8; two per side. Using Chuck Sternburg's trick, I cut a small piece of a business card the size of the cam bearing. Remove the middle cam bearing, insert business card, and re-torque. As an added reminder, I place a small piece of the business card on the stud JUST SO I DON'T FORGET TO REMOVE IT LATER. Now the cams are locked in place, and I can move onto removing the tensioner. In the picture, the tensioner is located between the camshafts to the extreme left, down about 8". As you can see, there's no access from the top. As you might imagine, access from the bottom is not so great, either. Plus, when I'm all through, I have to re-tension the timing chain, which I'm not so thrilled about either. I'll post an update after the tensioner is back in place, but for now, imagine I'll be on my back threading my arms around wires, pumps, belts, and hoses to get to the tensioner.