MTFCA Forum

I run Schrader 777 stems and hardware on my 30x3.5 tubes and have been very happy with them. Recently, one of my tires developed a slow leak and I removed the tube today. Turns out the leak was at the joint between the rubber tube and the base of the stem. I had driven the car for nearly a year with this tire/tube combination before the leak started. The clamp nut for the bridge washer wasn't very tight when I removed it, so I wonder if I didn't tighten it enough in the first place and it eventually worked loose.

How tight do other folks tighten their bridge washer nuts? I worry about splitting the tube rubber if I get it too tight.

Torqued to Ford spec. Used an 8" wrench.
Be sure to clean any & all old rubber bits that might be sticking in the ribs.

I tighten them enough to obviously crush the rubber and get a good resistance with a 6" open end wrench.

Tighten the bridge washer nut to about 10-15 inch-pounds. It should be snug but not overly tight to avoid damaging the rubber.

I like to leave 1/4" of the rubber stem when cutting the old stems off. This is then dressed down true to leave !/8" high shoulder around the hole. I like to think that leaving this helps to get a better seal and provides a little more rubber to crush when fitting the metal stem.

The only lubricant I use when fitting the stem is a little spittle. Tyre fitting lube/soap solution etc are to be avoided, as they aid the rubber to be squeezed out when applying tension to the nut and bridge washer. i tighten them enough so that they do not leak when tested in water like you do when looking for punctures.

Old time tubes were fabric reinforced around the valve stem hole. Nobody does that these days. It may help in some circumstances to apply a No 3 stick- on patch over the valve stem hole to give a little more thickness for the replacement metal stem. I would have done this on 20" Firestone TT tube recently if the customer did not have a ready replacement. The as new Firestone tube had let go at the outer margins of the valve stem base, on each side of the tube.

Hope this helps.
Allan from down under.

I've been cutting off rubber stems for years. Too bad no USA company is making tubes any longer. I like using 888's.

Wonder is some sort of sealant or rubber cement would help seal the joint? I do not know how often these valve stems are replaced.

I've never used a thing! I just get the bridge washer as tight as I can.

There are bridge washers, and there are bridge washers. There is some variety among originals, made by different companies at different times, but all have the raised ridge around the stem. That ridge presses into the rubber of the tube, squeezing it against the stem base for a good, tight seal. Modern bridge washers lack that ridge. They are perfectly flat on the bottom. I will not use them.

Steve's excellent photo illustrates why I leave a shoulder of the old stem intact when cutting off the stem. The shoulder left coincides with the relief in the bridge washer inside the raised ridge. This increases the footprint of the washer. As well as squeezing on the tube, it engages on the shoulder left from the old stem. It also means there is less chance of the rubber being squeezed out between the valve stem components.

Allan from down under.

The Model A Ford Bridge washers that the vendors sell have the raised ridge, but the outside shape is wider than Model T. The outer shape can be cut or ground down as needed.

https://www.snydersantiqueauto.com/prod ... &cat=41752