Indy Project Sled - Late-model Chaincase

Nov. 01, 2005 By ORC STAFF

Late-Model Chaincase and Brake Caliper

Cost: $150 (US)
Risks: Minor
Benefits: Drop-in brake pad replacement
Tools Required: Typical mechanic's toolkit
Parts Required: Chaincase and caliper
Mechanical Skill Required: Slightly above-average "shade tree" skills

Chances are, if you're reading this and you have a vintage Indy, you have either already changed your brake pads or you about to have to. And what you'll find when you get ready to do that is that it is not an easy job with the older brake caliper. Worse than that, if you want to upgrade to a better set of pads, you'll be out of luck because no aftermarket company that I know of makes pads with any of the fancy new compounds for the older style Polaris brake.

The solution to that problem is to install a late-model chaincase and brake caliper. It's not a small job and it's not terribly cheap, so the standard caveats regarding modifying an older sled apply. But if you are serious about keeping your old sled another couple of seasons but would like better braking, this is the only game in town.

You can purchase and install a newer chaincase for many different models and years, but I recommend the '96 XCR 440 SP chaincase because it comes with the Kelsey-Hayes caliper. As an added bonus, it comes with a set of pads installed. Polaris marketing must have been asleep at the switch when they priced this (shhhh! don't wake 'em!), but you get the chaincase, caliper and pads for not a significant amount more than just a set of pads.

Installation is not a simple job and will require some ingenuity on your part, but if you've ever changed a track, this isn't that much harder. Set aside a weekend for this, summer is a good time for this mod. This is a job that is made much easier by removing the hood too.

The first step of the installation requires virtual dismantling of your sled. This is a mod that fits well with other mods, which will save you the effort of dismantling and reassembling your sled over and over. If you're starting from scratch, begin by removing the rear suspension, the drive belt and the secondary clutch. The brake caliper is going to be replaced, so you may as well diconnect the brake line and drain out the brake fluid now. Then tip the sled on it's left side and remove the stock chaincase cover. Loosen and remove the chain tensioner, then remove the gears and chain. Keep track of the spacers, although more than likely you'll be aligning the gears from scratch after the new chaincase is installed.

Next you'll need to loosen the fafnir bearings on the clutch side of the drive and jack shafts, might as well loosen the collars too, you'll have to realign everything before you're through. At the risk of being overly redundant, check those bearings closely, if there is even a hint of roughness or noise, replace them now, while you've got everything yarded off. And more redundancy: buy the bearings from a bearing shop, not your dealer - same bearings, one quarter the price. Sorry Polaris, this is one place your pricing is out of line.

Go ahead and remove the track, installation and alignment is much easier with it out of the way.

Now remove the three carriage bolts that hold the chaincase in place and remove the bolts which hold the caliper to the case. You can tap the driveshaft out of the lower bearing with a plastic hammer, it should come out easily, but the jackshaft is another story altogether. I had a difficult time removing mine, as have others I've talked to, although there are people who say theirs dropped out as easily as the driveshaft. Hope you are one of the lucky ones. *grin* If not, carefully use a brass drift and the largest hammer you own. Careful not to nick the splines on the jackshaft! They can be cleaned up with a fine file if necessary.

Once the shafts are free, you can lift the old chaincase out. Keep track of any shims you might find behind the case, you'll be able to use those when you install the new case. Carefully remove the bearings from the old case and if they are in good condition, install them in the new case. If there is any doubt at all in your mind that they are bad, replace them now. In any event, use new snap-rings to hold them in place.

Now you can bolt the new chaincase into the sled. Remove the brake caliper first, you can install it later. Don't start thinking you're almost done though, you have to get everything aligned right first. To do that, push the drive and jack shafts into the chaincase bearings. Get them in as far as they'll go, you might want to install the gears on them, although if you had a difficult time removing the jackshaft, don't seat it all the way. Then note the way the other ends of the shafts align in the bearing holes on the clutch side of the bulkhead. They must both be perfectly centered for efficiency. If they are not, you'll have to loosen the chaincase bolts and place shims between the bulkhead and the case. Polaris sells an alignment tool that you bolt onto the clutch end of the shafts, but in my experience, you can get a good fix on it just by eyeballing the shafts.

Take your time on this step and get it right, it's well worth the effort. Anything you can do to make your drivetrain more free-running will make your sled perform better.

Once you have the chaincase aligned, you can put the shafts back in for real. Don't forget the track. *grin* (heh, will I *ever* live that down?)

More than likely, you will have to change the configuration of the shims behind your gears to get them aligned. Polaris made changes in the jackshaft for this chaincase, but you can get the old one to fit by reshimming the top gear. Again, take your time and make sure the gears are prefectly aligned using a straightedge. Once they are aligned, remove them one last time and put them back on with the chain, then tighten everything up and reinstall the tensioner.

Once you have the gears and chain back in, you can fasten down the fafnir bearings on the clutch side and bolt them and their carriers back into the sled.

Now you can drop the caliper in place over the rotor and bolt the caliper to the chaincase. Reconnect the brake line and refill/bleed the brake. Fill the chaincase with gear lube, check for leaks, reinstall the rear suspension, driven clutch and belt and you're good to go.

This is a big job, but you'll be rewarded with much improved braking and easier brake pad maintenance if you keep the sled long enough to wear out the pads.

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