I have a slow leak in two bbs detroits - I've had the tyres resealed and so suspect the valves. what do I need to do to replace them?
I've found a place selling bbs valves here (£17 each)
- do I just unscrew the old ones with a star tool and screw the new ones in?

 

Have you tried any of the stupid tricks first? I would start with applying soapy water and check for bubbles as a way to diagnose the problem.

Do these wheels have a chrome finish?

Best of luck, keep us posted.

 

Short of corrosion or cross-threading, I can't think of a failure that would make those valve bodies leak. The actual valve core may be bad - check that first. It's pretty close to being a literal "dime a dozen" part.
Funny story; a supposedly factory trained tech at my my local Jaguar dealer failed to realize that those wheels (just like any others) need valve cores, as a result he end up struggling for hours trying to inflate the tires after getting them mounted on my wheels.

 

thanks guys the wheels aren't chrome but they are in need of a refurb. good point about the cores - I will have a go replacing them first, worth a shot.


Fairly sure it's around the valves as when they were resealed the guy checked for punctures and cleaned up the inside of the rim. I'll try a bit of soapy water though too.

 

well i was surprised how easy it was to change the valve cores - all for less than the cost of a new valve! time will tell if I've stopped the leak.
One point of interest is that I had to modify the 4 way core removal tool as it wouldn't turn with the cross member in place (i.e. two of the 4 way ends, a tap and tapered thread thing). otherwise, simples!

soapy water didn't tell me anything, fwiw.

 

just to keep you all posted, as I bet you're wondering what happened. The front two tyres are still leaking. I've ordered new valves from sb wheels, cross your fingers for me that they solve the problem :-)

 

Inflate the tires to 35 or so pounds then squirt soapy water on each vale core. No bubbles? then they're not leaking. You had the tires resealed? What was done exactly? Alloy wheels can leak at the bead if corroded enough. A good tire shop has a liquid brush on rubber that they can brush on the bead to stop the leak. Try the soapy water around the rim diameter to see if bubbles appear first. The liquid rubber is only a patch. Once the tire is ever removed, the bead will need refinishing to a smooth surface.