Avid Ultimate brake lever refurbishments.

[Joe*Pro]

See dimensions of this shoulder bolt below. The 2 washers are then 1mm thick and upper one has 4.9mm hole, the other lower one has 4.3mm hole to sit on the base of the shoulder, over the thread. They are both 12mm outer diameter, but aslong as it covers the lever arm hole and inner bearing think outer diameter just needs to be 10mm or so.

The only similar bolt I can find is that M3 traditional head. But I don’t have a lathe. Wondering if I can tighten it in my drill chuck to spin it to file it down to a counter sunk version.

 

[Joe*Pro]

Plan B is to try a normal thread countersunk and then try a collar.

 

[Rampage]

Re:

Can you use a M4 CSK bolt with a piece of aluminium tubing for the shoulder?

 

[ishaw]

Re:

Either option should work. A bolt costs pennies (probably a few hundred) so it won't cost a lot to experiment. A lathe is just a big drill chuck after all.

 

[Joe*Pro]

Thought I’d update/finish the thread, in case anyone needs it for future reference...

So it took 6 months of occasional research, 4 pairs of good Avid Ultimates have come and gone, then finally 2 hours of manual labour with £17 of titanium bolts and titanium washers, with a £15 tap & die set from screw-fix to get the job done !!

But to back track a little, it turns out, Avid had 2 different size pivot bolts for the ultimates, one with the thinner 4mm thread hole the other with a thicker 5mm thread hole, you can tell by looking underneath at the width of the pivot bolt tip. I can only guess one for earlier models (With T15 Star bolt) and one for later models (With H3 allen bolt) I guess to make them more serviceable with a more common part size. So the more faded sets I bought for spares, to fix this brighter red set, didn’t fit at all. Doh!

i scanned around for dozens of titanium bolt options as per previous thread comments, including chats with SRP and others about making some, until I eventually found that: titanium rear derailleur jockey wheel bolts are almost exact replacements by design, they are just 1mm out on the thread M5 v M4 !!

So I figured that was my best option, how hard can it be to sand them down a little and re-thread the tips from M5 to M4, so after watching half a dozen YouTube clips on ‘tap & die’ work, I set to it...

the closest option: https://www.ebay.co.uk/itm/353484480288

 

[Joe*Pro]

 

[Joe*Pro]

Used the drill as my spinning drive, then pinned the thread and shaft between the file and Sanding block, to apply pressure. Turns out titanium clogs the file threads easily, so you have to move it up and down the file constantly for fresh grip, must have taken a good 30min sanding down 1mm off the thread and 0.2mm or so off the barrel shaft until they would fit perfectly through the lever arm.

then to re cut the thread to a smaller M4. Which on such a small bolt was pretty fiddley. The key was to file a good bevelled tip to gain purchase into the die to start the new thread off. But once going was great.

The 2nd matching bolt was half the time, easy once you know how.

Really pleased with the results, lovely snug fit and the design then is as per the originals and using another bike bolt, rather than a bodged alternative.

the other bit that turns out was key, was exact thickness of the washers, the titanium replacements I bought in both 4mm & 5mm diameter hole options where ever so slightly different in thickness, 1mm v 0.8mm. So was able to mix and match until perfect and then slight tighten until no play in the arms movement at all, brillian.

A good polish up and these will now soon be for sale on eBay, as in the frustration of the process prior to finding the jockey wheel bolt, I found an even more immaculate pair and impulse bought them at a ridiculous price. But learnt my lesson on parts appearing cheaper for a reason as per this make good effort.

 

[Joe*Pro]

 

[pw_pw_la]

When it rains Ultimates it pours!

Enjoyed reading along with this.

Epic, yet patient fix.

My overpriced in black and silver have just arrived.

Hopefully all the bolts will be in working order!

 

[pw_pw_la]

Also, assuming these are going on the Dirt/JMC tribute?

Any pics of said project?