My shop assistant gave me a hand removing all the idler wheels from the rear suspension and shafts. It didn't go easy at all but nothing does on a project like this. That's all part of the fun...isn't it?
New bearing and seal ready to be installed on the driveshaft. One of the parts I had a hard time finding was the lower chaincase seal. It's no longer available from BRP and the only place you'll find a new OEM part is on the shelf of your local ski-doo dealer, if you're lucky. I was lucky that my local dealer had 3 sitting on the shelf. I bought two of them, one for the 88 MX too. The other part that I had a hard time getting was the upper chaincase seal, it's also not available from BRP anymore. Again I was lucky and my local dealer had two on the shelf. Note: This same chaincase seal was used on many models up to 2003 including the PRS chassis and S-chassis. It is available from the aftermarket now, cheaper than OEM too. The lower chaincase seal is not the same as the 89 and up PRS chassis sleds, the driveshaft diameter changed in 89. I couldn't find this aftermarket but I'm sure it's available, somewhere.
When I installed the jackshaft bearing I noticed some play or movement between the bearing and the housing, that's not good. An incorrect bearing was installed on the shaft when I removed it, a flat outer race rather than a rounded outer race that is supposed to be installed. It also looked like a bearing had seized on the shaft and wore against the housing at some point. We'll take a look at the Mach 1 chassis and see if the housing is still installed and in good shape. We'll use that one if it's decent. Notice the jackshaft is pretty well centred in the opening? That's because I took the time to align and shim the chaincase, this removes unnessary loads on the drive bearings and prevents premature wear.
I was able to keep moving ahead and get the new track under the sled and get the driveshaft installed with new bearings. I also installed the lower gear (upper gear was already installed in order to align the chaincase and jackshaft) and chain. We're ready to put on the new gasket, cover and fill it with fluid.
This is basically how the sled sits now. As soon as the rear shocks arrive they can be put on the rear suspension and then it can be reinstalled, greased, with new bearings and new shocks.We decided to leave the belly pan off until the driveline was installed. It was way easier to the install the chaincase, jackshaft, and driveshaft without the belly pan in the way. We'll install it this week.
One thing I'd like to point out about the older PRS chassis Ski-doo's is that from 1989 on, they used internal drive sprockets and 121" tracks. Also, parts such as chaincase seals are much easier to get for the 89 and newer PRS sleds. If you have an older Formula, I recommend tracking down some used parts and upgrading to an 89 or newer driveshaft and rear suspension along with a 121" track. All the parts, including the track are much easier to find aftermarket, new OEM, and used.
Check out the lastes issue of Snow Goer Canada for part 1 of the story.
