Nail in tire question

[CDW6212R]

I think I felt the binding in my Mountaineer one time I had a tire almost flat from a nail. The tires were almost new, and I drove it slowly to a nearby tire shop I liked. They were authorized to repair it for the Continental warrantee I had, otherwise I would have plugged it in the parking lot where I discovered it.

 

[imp]

I think you've worded that wrong. If the tires were mismatched equally front to back, the two drive shafts would be running at the same speed. That wouldn't bother the AWD. Having just one tire sized wrong at either end makes the drive shafts run at different speeds, and the viscous clutch fights that. I never bought the 65/35 power variable garbage, the VC isn't sophisticated enough to do anything like that.

I just received a new viscous clutch last week, so I can rebuild my currently locked up AWD TC. The VC is actually very small, the size of any small clutch drum of an automatic trans. It weighs over 10lbs, I think it's a simple device which just resists very strongly any change in the two speeds(front and rear). An LS differential will wear out any clutches it has if a small spare is used, but that won't disable the diff. The VC can't take excessive speed differentiation for long. My 98 had black fluid when I got it at 159k, changed three times and it's always been too dark. Now it's locked up, it ruined my front differential last month. So I'll get it out in the next month or so and see what other damage might be in there. The VC is a sealed unit, when it leaks the TC fluid becomes black.

@CDW6212R
Good analysis......I'm trying to think through this dilemma, including the "creep in Park", and all the other claims I've read. Fact remains, the true AWD vehicle needs a third diff between the two driveshafts, to absorb any speed differences front to rear. I think a few makes did that, Subaru maybe being one. Expensive though, compared to Ford's scheme.

For now, would you agree with this premise: Put a 10% difference in rolling diameter on one tire on both front and rear axles, and while moving straight ahead, both driveshafts will turn at the same speed? imp

 

[Mbrooks420]

I can attest to the creep in park. I got called out of one of the biggest work meetings of my life (coordinating the controls and data engineering aspect of moving an aerospace manufacturer) by a call over the PA of “ would the owner of a green Mercury Mountaineer, license number xxxxxx report to the guard shack. Your car is blocking traffic and needs to be moved immediately or it will be towed”.

It has rolled out of its spot and blocking an isle of traffic. A maintenance guy had stuck a hammer under the tire. They were puzzled. He was like “we came out to get the plate and noticed it was moving really slow. It looks like it’s in park”. He originally thought it was a stick, and I left it in neutral. I played dumb, and pretended to be baffled.

 

[CDW6212R]

@CDW6212R
Good analysis......I'm trying to think through this dilemma, including the "creep in Park", and all the other claims I've read. Fact remains, the true AWD vehicle needs a third diff between the two driveshafts, to absorb any speed differences front to rear. I think a few makes did that, Subaru maybe being one. Expensive though, compared to Ford's scheme.

For now, would you agree with this premise: Put a 10% difference in rolling diameter on one tire on both front and rear axles, and while moving straight ahead, both driveshafts will turn at the same speed? imp

Yes, that's what I was saying in my second sentence. You can identify mismatched tires and combine two that match the diameters of the other two, you can put those at each end and it'll work fine.

My locked AWD right now seems to not roll at all, it never really has since I got it. There's a noise when parked in what seems like the right rear brake, as if it's creeping slowly, but I've never been parked with it like that on a hill long enough to see if it would move. So I haven't needed the parking brake with the front drive shaft out with the VC locked up.

My Mercury creeped every time when I had the front shaft out and no parking brake. It will do it on any very slight incline. That's the TC I'm about to rebuild, to swap into my Explorer. I'm sure that one should only need the normal rebuild parts. The bad one might need some more.

 

[Indispensable Explorer]

I have never heard of use of a plug and patch both. If it were done, the plug would have to be inserted first, then that portion of it protruding inside of the tire would need to be carefully removed before the patch was applied. Not a bad idea, though but I've never seen it done. imp

I think he’s referring to the patches that have a plug attached to them?

I'm talking about the kind of repair that tire shops do, using a separate plug and patch. Unfortunately, this process is more than most diy guys are willing to handle because the tire has to be dismounted and rebalanced. When I repair a flat tire I do the following:
1) Remove tire from wheel
2) Remove foreign object from tire
3) Probe injury to ensure direction of hole
4) Use a drill to clean out the hole and prepare for plug
5) Apply cement to plug and pull through injury
6) Cut off both ends of the plug flush with the tire
7) Grinde down the plug(and a 2" x 2" area around the plug) on the inside of the tire so the area is even(it's best if there is no steel cord showing)
8) Clean with alcohol and a scraper to ensure debris is off of buffed area
9) Use shop vac to remove any debris
10) Apply thin layer of cement to buffed(ground) area
11) Take patch and place on top of cement(cement must be dry and tacky)
12) Stitch patch to ensure proper bondage
13) Remove plastic patch protector
14) Cover entire buffed area with repair sealer(liquid rubber)
15) Reinstall tire and balance the assembly
I'll get a few pictures when I'm at work tomorrow if that helps clear things up.

 

[Mbrooks420]

When I repair a tire i:

turn the wheel to access it.

Jam the reamer tool in.

Install the old school plug.

Never worry about it again.

 

[CDW6212R]

When I repair a tire i:

turn the wheel to access it.

Jam the reamer tool in.

Install the old school plug.

Never worry about it again.

I do the same, but with a little more finesse than jamming it in.

Plus my plugs require no cement, I wouldn't have any plug that requires cement, that's poor technology and it will eventually leak.

 

[imp]

I'm talking about the kind of repair that tire shops do, using a separate plug and patch. Unfortunately, this process is more than most diy guys are willing to handle because the tire has to be dismounted and rebalanced. When I repair a flat tire I do the following:
1) Remove tire from wheel
2) Remove foreign object from tire
3) Probe injury to ensure direction of hole
4) Use a drill to clean out the hole and prepare for plug
5) Apply cement to plug and pull through injury
6) Cut off both ends of the plug flush with the tire
7) Grinde down the plug(and a 2" x 2" area around the plug) on the inside of the tire so the area is even(it's best if there is no steel cord showing)
8) Clean with alcohol and a scraper to ensure debris is off of buffed area
9) Use shop vac to remove any debris
10) Apply thin layer of cement to buffed(ground) area
11) Take patch and place on top of cement(cement must be dry and tacky)
12) Stitch patch to ensure proper bondage
13) Remove plastic patch protector
14) Cover entire buffed area with repair sealer(liquid rubber)
15) Reinstall tire and balance the assembly
I'll get a few pictures when I'm at work tomorrow if that helps clear things up.

@Indispensable Explorer
Very complete! Thank you.

 

[Mounty99]

Thanks for all the good advice / discussion. Received my kit last week, plugged the tire, then had to leave town for ten days. Back home now, and tire is holding air perfectly. Hoping it stays that way! Anyway, below is a pic of the freshly plugged tire, and thanks again for all the replies.

 

[Mounty99]

Freshly plugged tire (with soap checking for leaks):

 

[RandomNerd2000]

Drive careful on that for a bit until you know you know it's safe, since it's close to the edge of the read and tire stores pitch a fit about anybody fixing a tire with a hole there. I've never had an issue there though, and I've plugged them there myself. Good work.