Leak from tyre valve stem

[sethmopp]

I have a leak that started overnight from the rear wheel. At first I thought that I had a pucture but on close inspection I could find nothing. As I was in a hurry, I inflated the tyre and kept my eye on the tyre pressure monitor display. During the journey it lost no pressure, but when I came back to the bike a few hours later it had lost pressure. I had a new trye fitted (it was due one) but the problem persists. I traced it to where the valve comes through the wheel and also found the nut was loose. After tightening this up, the leak seems less. My question on this is, are there seals on the TPM unit/ valve that can fail and cause this? If so, it's probably a warranty issue (2012 GSA)

TIA

 

[Bendy toy]

I have recently removed TPS sensors to have the wheels refinished. The nut on the valve stem holds the valve and sensor to the wheel. The seal is a conical O ring. Any leaks will be due to loose nut damaged seal or corrosion in the rim valve hole.

Also check the shraeder valve insert is properly screwed in.

 

[sethmopp]

Thanks, that was the bit of info I was looking for. I did the soapy water test, as did my local bike shop and both got same results. The leak was from where the valve comes through the rim, a mass of foamy bubbles round the base of the valve stem was the giveaway.

 

[Bendy toy]

Because corrosion was getting under the paint and because it can quickly chew into the base metal I'm having the wheels recoated. To avoid kak getting under the finish, the valve holes are not being masked off. Ditto the disc lugs and rear wheel mounting face. Time will tell if I've goofed on those two.

 

[autogs]

imo you should mask rear wheel face and disc lugs,bm brake discs dont need any encouragement to warp
when my cast wheels were powdercoated i asked for this to be done just in case they coated the lot.

 

[Bendy toy]

With solid discs I would definitely mask the disc mounts, but on floaters I'm hoping there will be enough flexibility in the mounts to accommodate any slight differences. I have put cheap M8 bolts into each bolt hole but not screwed them down. The coating should be similar on each boss with a ridge around the bolt threads which will be trimmed flush with a Dremel.

TBH its a slight gamble because powder coat is so tough. But Ive offset that against a near certainty than corrosion will set in from the edges if I mask off the whole top of the brake bosses.

 

[autogs]

one things for sure,time will tell

 

[Smug]

I have a leak that started overnight from the rear wheel. At first I thought that I had a pucture but on close inspection I could find nothing. As I was in a hurry, I inflated the tyre and kept my eye on the tyre pressure monitor display. During the journey it lost no pressure, but when I came back to the bike a few hours later it had lost pressure. I had a new trye fitted (it was due one) but the problem persists. I traced it to where the valve comes through the wheel and also found the nut was loose. After tightening this up, the leak seems less. My question on this is, are there seals on the TPM unit/ valve that can fail and cause this? If so, it's probably a warranty issue (2012 GSA)

TIA

This is what you need:-

36 31 8 520 871

SET: REPAIR KIT, TIRE PRESSURE MONITOR VALVE - RDC

 

[Bendy toy]

one things for sure,time will tell

It sure will.

CJ Ward are short staffed due to holidays so it will be mid June before I get the wheels back.

 

[WindyChuffer]

Careful - those tyre pressure sensor valve stems are really brittle....

 

[Bendy toy]

Careful - those tyre pressure sensor valve stems are really brittle....

My alloy wheel sensor valves unscrewed quite easily but I was concerned because a brass valve cap (on the wire wheels) had almost welded itself to the valve stem due to salt. They will be getting plenty of WD40 before they are removed. Its now got plastic caps BTW.

 

[Andy B]

Leak from tyre valve stem
I have a leak that started overnight from the rear wheel. At first I thought that I had a pucture but on close inspection I could find nothing. As I was in a hurry, I inflated the tyre and kept my eye on the tyre pressure monitor display. During the journey it lost no pressure, but when I came back to the bike a few hours later it had lost pressure. I had a new trye fitted (it was due one) but the problem persists. I traced it to where the valve comes through the wheel and also found the nut was loose. After tightening this up, the leak seems less. My question on this is, are there seals on the TPM unit/ valve that can fail and cause this? If so, it's probably a warranty issue (2012 GSA)

Have you ruled out the possibility that the valve hole hasn't been damaged? I had this problem some years ago and it was caused by the chap who changed the tyre. He caught the TPM unit when breaking the bead and it caused the hole to become out of true. One new wheel later........!

 

[sethmopp]

This time I don't think dealer damage is the problem. It was doing the same before and after the tyre change. Apparently this issue is known to my (relatively) local BMW emporium

 

[Nick dj]

Ultra seal?

My front tyre has very slowly dropped in pressure from new(so cannot be corrosion), I put this down to being wire wheels. I plan to put Ultra Seal in when I change the tyre. I have used this for years and trust it.

Will try tightening it, to see if it is just lose.

Nick

 

[sethmopp]

I tightened mine up, it's losing less. Dealer has an open day on saturday so will talk to a mechanic then. May get it dealt with under warranty next time as they'd have to get a new part if it's needed.