Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Larry Rubin on September 15, 2022, 10:14:02 pm

Title: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: Larry Rubin on September 15, 2022, 10:14:02 pm
I think there's air leak at a tire valve on one of the rear duals.  Will do a bubble test to confirm.  If it is leaking at the valve, can I just purge the air from the tire, R/R with a new valve without having to get the weight off the tire?

I'm assuming its a Schrader valve and a size I get from an auto supply.

Thanks,
Larry
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: craneman on September 15, 2022, 10:15:17 pm
I usually change them when they still have pressure.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: bigdog on September 16, 2022, 12:33:51 am
I'm with craneman.
Just keep a firm hold of the insertion tool or the valve will launch a lot further than you might imagine and you will have a heck of a time finding it. I would recommend having a valve tool that has a screw driver type handle over the very small T handle style.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: Jeff & Sandy on September 16, 2022, 06:47:33 am
Are these valve replacements a universal size? I have a slow leak and suspect the valve.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: craneman on September 16, 2022, 10:04:02 am
Yes, though they do come in different lengths both work.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: oldguy on September 16, 2022, 10:16:36 am
Why no check to see if the valve is leaking. I like using kids bubble mix an put it over the valve stem
and check if it is leaking. If it is the outside dual you might need a mirror.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: wolfe10 on September 16, 2022, 10:55:12 am
A little spit will also identify a leaking Schrader valve.

May just be a little loose, or perhaps someone may have bent it and it will need replacement.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: dsd on September 16, 2022, 10:59:16 am
Yes attempt to recheck the install torque. It may of just relaxed. Yes i change pressurized. The rear inboard are a pain and i actually got a long removal tool to accommodate the change. Also shown is a tool to catch removed valve stem
Scott
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: bigdog on September 16, 2022, 12:56:25 pm
Yes attempt to recheck the install torque. It may of just relaxed. Yes i change pressurized. The rear inboard are a pain and i actually got a long removal tool to accommodate the change. Also shown is a tool to catch removed valve stem
Scott
I asked several tire shops why the outside dual valves were always pointed inwards. Just the way it's always been done was the answer. So I asked if there was a technical reason to point it inwards. No, Just the way it's been done was the answer by all the shops.

SOOOO.  Last time my tires were dismounted from the wheels. I had them put it new valve stems and gaskets then turn the outside valve 180 degrees so it points outward. And it works and has not had any leak down issue from the redirection.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: dsd on September 16, 2022, 04:05:45 pm
Jerry Kinda bugs me having them stick out worried rad trash could damage them. You could go to the TR542 stems.  Straight out and short. I may even order them for my front wheels. (TR542) Alcoa O-Ring Seal Valve Stem | Tire Supply Network (https://tiresupplynetwork.com/products/tr542?_pos=5&_psq=tr549&_ss=e&_v=1.0)
Scott
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: craneman on September 16, 2022, 04:12:42 pm
I asked several tire shops why the outside dual valves were always pointed inwards. Just the way it's always been done was the answer. So I asked if there was a technical reason to point it inwards. No, Just the way it's been done was the answer by all the shops.

SOOOO.  Last time my tires were dismounted from the wheels. I had them put it new valve stems and gaskets then turn the outside valve 180 degrees so it points outward. And it works and has not had any leak down issue from the redirection.

The reason was the front and rear tires could be interchanged on the road if needed. I've seen a missing outer on city trucks making it to a tire shop.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: bigdog on September 16, 2022, 07:53:49 pm
The reason was the front and rear tires could be interchanged on the road if needed. I've seen a missing outer on city trucks making it to a tire shop.
That makes perfect sense craneman. Never had to do that in 1,500,000 miles in my tractor though. I guess I was super lucky and never even had one flat on my tractor in all those miles.

Won't happen on the coach either with us having coachnet. ^.^d
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: bigdog on September 16, 2022, 07:55:28 pm
Jerry Kinda bugs me having them stick out worried rad trash could damage them. You could go to the TR542 stems.  Straight out and short. I may even order them for my front wheels. (TR542) Alcoa O-Ring Seal Valve Stem | Tire Supply Network (https://tiresupplynetwork.com/products/tr542?_pos=5&_psq=tr549&_ss=e&_v=1.0)
Scott
They don't stick out far enough to have me worried about highway trash.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: oldguy on September 17, 2022, 12:59:06 am
The inner and outer duals can be interchanged and the fronts too as Chuck said. A spare can be
put anywhere it you have one, if the valve stems are pointed inward.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: Old Toolmaker on September 17, 2022, 08:48:19 am
I think there's air leak at a tire valve on one of the rear duals.  Will do a bubble test to confirm.  If it is leaking at the valve, can I just purge the air from the tire, R/R with a new valve without having to get the weight off the tire?

I'm assuming its a Schrader valve and a size I get from an auto supply.

Thanks,
Larry

Since I don't see a direct answer to your original question: Yes.

Just make sure the good tire is properly inflated.  The last thing you want to do to a truck tire is deflate it under load.  Truck tires don't take well to folded sidewalls.

Automotive Schrader valves are all the same basic standard.  Motorcycle shops sell the short valve cores with the red seal as "high speed" and less likely to unseat at high tire RPMs.

Art
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: EddieNel on September 17, 2022, 07:09:11 pm
Ive got one thats leaking but only when the temps are in the 20's.
Title: Re: Do I need to get weight off dual rear tire to replace a leaky Schrader valve?
Post by: Pierce & Gaylie Stewart on September 17, 2022, 08:59:21 pm
I had a cheap tire gauge damage a valve. I just used a metal valve cap with the tool in the end to pull the damaged one out, held my finger over the stem and then screwed the new core in. Other than a difficult angle on one of the rear tires to get a core in, it's not as urgent as a front tire.

If you don't want to do it now, I've just used a metal cap with a rubber washer inside and just tightened it down. Didn't leak and I changed the core later that day. Good if you don't have a core with you and have to drive to a car parts store.

Quite a few tire manufacturers say that if the tire goes flat with the weight of the coach on it, you need to replace it.

One owner had a rear flat in Mexico, took the tire off and drove across Mexico into the U.S. before he had a new one put on. Don't understand that one.

Smart money always has a spare on board and a hose to refill the tire. A small compressor that goes over 120 psi is best.

Pierce