"Snail" Brake Adjusters

[geodon]

What actually DRIVES these thingies as you turn the adjuster?

I've got one that has "lost its drive" when I turn it. Are they splined on? If so I can't see evidence of it. Friction? Hardly a positive drive!

I'm sorely tempted to use a couple of spot welds to lock it to the head of the 3/16ths UNF bolt that attaches it to the adjuster bolt! As you adjust the brakes clockwise, the thread will lock & it thus MUST turn. So long as I avoid going counterclockwise and risk it unscrewing!

[pop058]

PM Col Coleman as he recently got a full parts kit of snails. Not a lot of money I believe and heaps less hassle to replace them with new rather than trying to repair them.

HTH

[Bigbjorn]

What actually DRIVES these thingies as you turn the adjuster?

I've got one that has "lost its drive" when I turn it. Are they splined on? If so I can't see evidence of it. Friction? Hardly a positive drive!

I'm sorely tempted to use a couple of spot welds to lock it to the head of the 3/16ths UNF bolt that attaches it to the adjuster bolt! As you adjust the brakes clockwise, the thread will lock & it thus MUST turn. So long as I avoid going counterclockwise and risk it unscrewing!

Would these not be 3/16" x 32 BSF? I realise I am diverging to the dogmatic/pedantic side but they are old Brits. 3/16" x 32 NF was declared obsolete in 1950 in preparation of "Unification" of British and Canadian thread standards with the USA.

THe US has not used fractions of an inch to describe threads under 1/4" since then. Nowadays a 3/16" NF is a No.10 x 32. A tad different in diameter, 0.1875 against 0.190. The number sizes below 1/4" were adopted at the request of the ASME. The number represents the wire gauge from which the small fasteners are made.

[geodon]

Brian, they could well be! I have not put a thread guage on them! However these look like they are aftermarket replacements & I doubt they will be BSF.

As for replacing them, at $11 a pop per adjuster kit, it's no biggie. BUT that does not guarantee they won't slip in the future. Even if I do replace them to get a better set of teeth on the snails, I may weld them on the make sure. Removal later? Just grind them off with a Dremel or small angle grinder.

I suspect the OE ex-factory ones had snail cams that were peened onto the rotating shafts, yes?? The aftermarket variety found it more expedient to just rely on the crush factor to transmit drive, I suspect.

[gromit]

Brian, they could well be! I have not put a thread guage on them! However these look like they are aftermarket replacements & I doubt they will be BSF.

As for replacing them, at $11 a pop per adjuster kit, it's no biggie. BUT that does not guarantee they won't slip in the future. Even if I do replace them to get a better set of teeth on the snails, I may weld them on the make sure. Removal later? Just grind them off with a Dremel or small angle grinder.

I suspect the OE ex-factory ones had snail cams that were peened onto the rotating shafts, yes?? The aftermarket variety found it more expedient to just rely on the crush factor to transmit drive, I suspect.

I fitted some of the 'aftermarket' ones to my Series 1 and the material they are made from is dubious (Nickel plated cheese ?)
They quickly lost drive and I think I resorted to weld to hold the cam in position.

The OEM ones are fit-for-purpose some of the aftermarket ones are not...


Colin

[geodon]

This is the adjuster that failed. The snail is crushed against the rotating bolt by a smaller bolt that screws into it.

https://www.aulro.com/afvb/images/imported/2012/08/1825.jpg

This what arrived from FourWheelDrives. The snails are peened onto the rotating bolt

https://www.aulro.com/afvb/images/imported/2012/08/1826.jpg

https://www.aulro.com/afvb/images/imported/2012/08/1827.jpg

Once installed, I spot welded snail onto the shaftand ground it down a bit

https://www.aulro.com/afvb/images/imported/2012/08/1828.jpg

Job done? Not quite! The spot weld gave way so I had to dismantle for the THIRD time and weld the snail on with Extreme Prejudice.