Is your trusty 1999 Polaris Indy 500 suddenly bogging down, refusing to idle correctly, or fouling spark plugs on the clutch side? You’ve probably checked the carbs a dozen times, but the real culprit might be hiding right behind the primary clutch. A failed PTO-side crankshaft seal is a common issue on these classic sleds, and ignoring it is a fast track to a seized engine.
You’re probably thinking a crank seal replacement sounds like a massive, expensive job best left to the dealer. We’re here to promise you that with the right tools and a bit of patience, this is a job you can absolutely conquer in your own garage. This is the ultimate 1999 polaris indy 500 pto crank seal diy guide you’ve been searching for.
In this post, we’ll walk you through diagnosing the problem, gathering the essential tools, and a detailed, step-by-step process to get that new seal installed perfectly. You’ll save a stack of cash, learn a ton about your machine, and get that Indy running crisp and strong again.
Why a Leaky PTO Crank Seal is a Ticking Time Bomb for Your Indy 500
Before we bust out the tools, it’s crucial to understand what’s at stake. The crankshaft seals on your two-stroke engine are incredibly important. They have one job: to keep the pressurized fuel/air/oil mixture inside the crankcase and the outside air out.
The PTO (Power Take-Off) side is the clutch side of your engine. When this seal fails, it creates an air leak directly into the crankcase for that cylinder. This unmetered air leans out the fuel mixture, leading to a cascade of problems.
Symptoms of a Failed PTO Crank Seal
A bad PTO seal isn’t always obvious, but it leaves a distinct trail of clues. Look out for:
- A Lean Bog: The engine hesitates or bogs down when you hit the throttle, especially from a standstill. This is because the lean mixture doesn’t have the combustion power it needs.
- Erratic or High Idle: The extra air can cause the engine to idle way too high or hunt up and down as it tries to stabilize.
- Hard Starting: A proper fuel/air mixture is needed to start. An air leak disrupts this, making the engine difficult to fire up.
- Melted Piston: This is the worst-case scenario. A lean mixture burns dangerously hot. Over time, this extreme heat can melt a hole right through the top of your PTO-side piston, resulting in a catastrophic engine failure.
Tackling this job yourself offers huge benefits of 1999 polaris indy 500 pto crank seal diy. You’re not just saving hundreds in labor costs; you’re actively preventing a multi-thousand-dollar engine rebuild. That’s a weekend well spent.
Essential Tools and Parts for the Job
Having the right gear on hand before you start is the key to a smooth, frustration-free project. You don’t need a professional shop, but a few specific tools are non-negotiable.
Required Tools
- Polaris Primary Clutch Puller: This is the most important special tool. Do not try to use a gear puller or a hammer. You need the correct bolt-style puller for your P-85 clutch.
- Torque Wrench: Absolutely critical for correctly tightening the clutch bolt during reassembly.
- Socket & Wrench Set: A good metric set will cover every bolt you need to remove.
- Seal Puller Tool: A small, hooked seal puller makes life easy. Alternatively, you can use the “sheet metal screw” trick we’ll cover later.
- Impact Wrench (Optional): An electric or air impact can make removing the clutch bolt much faster.
- Gasket Scraper: A plastic razor blade or scraper is best to avoid gouging the aluminum case.
- Shop Supplies: Brake cleaner, shop towels, and a dab of grease.
Necessary Parts
- New PTO Crankshaft Seal: Don’t cheap out here. Get a quality seal from Polaris (OEM) or a reputable aftermarket brand like SPI or Winderosa.
- Loctite: You’ll want some Blue (medium strength) for smaller bolts and Red (high strength) for anything specified.
The Complete 1999 Polaris Indy 500 PTO Crank Seal DIY Guide
Alright, it’s time to get our hands dirty. This detailed guide will show you how to 1999 polaris indy 500 pto crank seal diy safely and effectively. Take your time, stay organized, and follow each step carefully.
Step 1: Safety and Preparation
Position your snowmobile in a well-lit, flat area. Disconnect the spark plug wires to prevent any chance of an accidental start. Give the clutch and engine area a quick cleaning to keep dirt from falling into the engine once it’s open.
Step 2: Gaining Access
Open or remove the hood for maximum working space. Remove the drive belt by pushing down and inwards on the secondary clutch to open the sheaves. Next, unbolt and remove the exhaust pipe and canister that are blocking access to the recoil starter housing.
Step 3: Removing the Primary Clutch
This is often the most intimidating step. Use your impact wrench or a breaker bar to remove the main clutch bolt. Now, thread your Polaris clutch puller into the same hole by hand until it stops. Using a wrench, tighten the puller. It will put immense pressure on the crankshaft, and with a loud “POP,” the clutch will release from the tapered shaft. Never hit the puller or clutch with a hammer.
Step 4: Removing the Recoil Housing
With the clutch out of the way, you’ll see the recoil starter housing. Remove the handful of bolts (usually 10mm) holding it to the crankcase. Gently pull the housing off. The PTO crank seal is now staring you right in the face, pressed into the engine case.
Step 5: Extracting the Old, Leaky Seal
Here’s where you need to be careful. The goal is to remove the old seal without scratching the crankshaft or the aluminum housing it sits in. A scratch creates a new leak path.
The Pro Method: Use a dedicated seal puller. Hook the end behind the seal’s metal body and carefully pry it out.
The DIY Method: Carefully drill a very small pilot hole in the metal face of the seal. Thread a small sheet metal screw into the hole, being careful not to go too deep. Once the screw has a good bite, use pliers or a claw hammer to pull on the screw, extracting the seal.
Step 6: Cleaning and Installing the New Seal
This is a critical step in our 1999 polaris indy 500 pto crank seal diy guide. Thoroughly clean the housing where the seal sits with a rag and some brake cleaner. Make sure there is no old rubber, oil, or debris left.
Take your new seal and apply a thin film of 2-stroke oil or assembly grease to its outer edge. This helps it slide in smoothly. Carefully start the seal into the bore, ensuring it’s perfectly straight. Use a large socket or a seal driver that matches the outer diameter of the seal and gently tap it into place until it is flush with the case.
Step 7: Reassembly and Final Torque
Reassembly is the reverse of removal. Reinstall the recoil housing. Before putting the clutch back on, ensure the tapered end of the crankshaft and the inside of the clutch are perfectly clean and dry. Any oil or debris here can prevent the clutch from seating correctly.
Slide the clutch back on, apply a drop of Blue Loctite to the clutch bolt threads, and tighten. You must use a torque wrench here. Torque the clutch bolt to the factory specification, which is typically around 50-60 ft-lbs for these models. Reinstall your exhaust, belt, and spark plug wires.
Common Problems and Pro Tips for a Flawless DIY
Even the best plans can hit a snag. Here are some solutions to the most common problems with 1999 polaris indy 500 pto crank seal diy projects and a few extra tips.
The Clutch That Won’t Budge
If your clutch won’t pop after tightening the puller, try tightening it as much as you can, then leave the pressure on it. Sometimes a sharp, firm tap on the head of the puller bolt with a hammer can shock it loose. A little bit of heat from a propane torch on the clutch’s inner sheave (never on the crankshaft!) can also help it expand and release.
Avoiding Scratches and Gouges
We can’t stress this enough: be gentle when removing the old seal. A deep scratch on the crank or in the case will cause the new seal to fail immediately. If you use the screw method, wrap the jaws of your pliers in tape to prevent marring the case surface.
The Post-Repair Test
Once everything is back together, start the sled and let it idle. Listen for a smoother, more stable idle. Check around the seal area with a flashlight for any visible signs of oil mist. The true test is on the snow, where you should notice a significant improvement in throttle response and a lack of bogging.
Sustainable and Eco-Friendly Best Practices for Your DIY Project
Being a gearhead doesn’t mean we can’t be mindful of the environment. A sustainable 1999 polaris indy 500 pto crank seal diy approach is easy and responsible.
- Proper Disposal: Collect any oils or cleaners on a rag or in a drain pan. Dispose of these materials and the old metal seal at your local auto parts store or recycling center.
- Smart Cleaners: Opt for non-chlorinated brake cleaners, which are less harmful to the environment.
- Reduce & Reuse: By doing this repair, you’re extending the life of your classic snowmobile, which is the ultimate form of recycling! This is a core part of any good 1999 polaris indy 500 pto crank seal diy care guide.
Frequently Asked Questions About the 1999 Polaris Indy 500 PTO Crank Seal DIY
Can I reuse the old crank seal if it doesn’t look damaged?
Absolutely not. Crank seals are a one-time-use part. They harden with age and heat cycles, and removing them almost always causes damage, even if it’s not visible. Always install a new one.
How do I know if it’s the PTO or MAG side seal that’s leaking?
The easiest way is to perform a leak-down test on the engine. However, a good rule of thumb is to check your spark plugs. If the PTO-side (clutch side) plug looks white, ashy, or cleaner than the other, it’s a strong indicator of an air leak on that side.
What happens if I ignore a bad crank seal?
Ignoring it will, without a doubt, lead to engine failure. The constant lean condition will overheat the piston, causing it to score the cylinder wall or melt entirely. This turns a simple $20 seal replacement into a $1,500+ top-end engine rebuild.
Do I really need a torque wrench for the clutch bolt?
Yes, 100%. Under-tightening can allow the clutch to slip on the crank taper, damaging both parts. Over-tightening can stretch the bolt or damage the threads in the crankshaft. It’s one of the most important torque specs on the entire machine.
You’ve done it. By following this guide, you’ve tackled a critical piece of engine maintenance, saved yourself a ton of money, and ensured your Indy 500 will be ripping through the powder for years to come. That feeling of accomplishment and the crisp throttle response on your next ride is the ultimate reward.
Now get those tools out, take your time, and enjoy the satisfaction of a job well done. We’ll see you on the trail!
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