When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So ever since I finished my build back in June I've had an oil leak at the front of the engine. During the build I put a post up about some concerns I had about the front main seal based on the conditionof the crank. Given the fact that I had been working on the car for over a year at that point, I decided to just put in a new OEM seal and see what would happen. Since it's been leaking I've been researching remedies and decided to try a Redi-Sleeve (National # 99145, from Rock Auto). I had planned to pair this with another new OEM Mazda seal. I spent yesterday afternoon pulling everything apart (radiator, sway bar, valve cover, timing covers, etc.). Tonight I attempted to fit my new Redi-Sleeve and; much to my dismay, it slid right over the crank with no force whatsoever. It's about 1mm too big all around.
I have attached pics of the crank damage and I'm seeking advice (yes, that's RTV on the front of the oil pump courtesy of the previous owner. Obviously I'm not the first one to deal with a leaky main seal on this engine). After I discovered that the sleeve was too big, I tried sanding the crank with 800 grit sandpaper, but as you can see from the pics the damage is still there. So at this point which of the following should I try:
1. Lube the seal an install it and hope for the best.
2. Try to find another sleeve that actually fits.
3. Try some kind of epoxy fix to fill in the scratches
4. ??????
Here's the most embarrassing part. During disassembly I noticed that the cam seals had been leaking (they were replaced with new Mazada OEM parts when I did the timing belt). My first thought was "I better reaplce those too', so I put a 10mm on the cap that houses the seals so I could get them out easily. That's when I discovered that I failed to tighten these bolts when I loosend them to replace the seals the first time. I"M A DUMBASS. So at this point it's entirely possible that the quart of oil I have been losing every thousand miles has been due to my negligence on the cam caps and not the front main seal that I had been so worried about.
I already pulled out both cam seals and the crank seal. I know the cam seal is the obvious and easy fix. Should I just throw the crank seal back in (not my preferred solution)? If not, what would you advise?
When you're done laughing at me, any guidance you can give is appreciated. LOL.
How smooth did you get those scratches with the sandpaper? Can you feel any burr or are they fairly smooth? I'd sand it very, very gently until you can't feel a burr. You're not going to remove those divots, but you need to make sure they're not going to cut the seal. Sand around the circumference, not front-to-back. The worst thing to do is create scratches that travel out from the sealed to the unsealed side. Then I'd clean the hell out of it (get that sanding grit OUT), apply some grease, and put in a new seal. I don't think you're going to get a huge oil leak from this, but you may end up going through front main seals more quickly than normal.
I did the same thing you did, except with the cap over the CAS O-ring, back in my younger days. It happens.
They make crank seal repair kits. Basically a metal sleeve you drive onto the crank to create a smooth surface. You'll need to measure the crankshaft itself to figure out which one you need unless a website lists one directly for Miata's. Here is an example of one for a 1.6
I ended up using Timken part # 99144. I would recommend using a dremel to cut a slit into the removeable ring that's used to tap the part in place. You'll need to remove the ring once the sleeve is installed; the slit really helped in getting it off (odd angle, hard to get pliers on it). I also wrapped the sleeve with a piece of scotch tape when I installed the the new seal. This ensured that the seal lip didn't catch on the sleeve when sliding it into place (remove the tape when you;re done). Since doing this repair I haven't seen any oil leaking from the front main seal.
One last note, I installed mine with the removeable ring facing out. If you do it the way the instructions say, you won't be able to remove the ring because it will be too far inside the oil pump. I was concerned about it rubbing on the back side of the crank seal. I used a small section of PVC to tap it into place as the provided cap didn't work very well when installing the sleeve backwards. All of this probably seems a bit cryptic, but it will make sense when you have the part in your hand.
No that all makes 100% sense. I’ve ordered a sleeve off Amazon ( same part number you suggested) thanks for the tip of installing backwards and definitely wouldn’t have thought of the tape with the new seal! Thanks!
im debating taking off the oil pump since a I have the engine out of the car and oil pan is coming off to drill for turbo return anyways.. just not sure if it will be too much trouble to reseal it back in.
You might be wondering why not replace the crank at this point but I really don’t want to wait another two to three months for new bearings 😂
11-02-2020, 08:04 PM
Scratched crank; leaky front main seal
0
