Put the front brake back together on my 70 TR6C and went to connect at the lever and basically had nothing but slack. Worked with the adjuster rod on the brake cam and got it as tight as it would go. Moved the adjuster at the lever all the way out and barely had any grab. Thought maybe I was missing some type of ferrule where the cable meets the brake anchor plate. In looking at pics it looks as if my whole cam mechanism is moved forward.
I could tear into the anchor plate to make sure everything is good in there but wondering if I am missing something simple.
I'm not completely sure, because your top picture doesn't show enough of it, but it appears to be the wrong cable - the outer should end in a ferrule that sits in the top of the brake plate abutment(?) and the cable should be about parallel to the fork slider.
If it's a '68 cable, the inner is longer, because the abutment for the outer is about below the rear pivot and then the inner runs to the end of a lever straight down from the front pivot. If you enter "1968 triumph" into your preferred internet search engine, look at the tls front brake plates in the returned images.
The cable is from an early twin leader or it's simply been made wrong. You have the correct lever and adjuster as I recall them. So, reset the adjuster rod so both brake shoes touch the drum at the same time. Then get the correct length cable (or shorten yours).
You also might want to check the length of the rod between the two brake cams. Workshop spec is 6.5" in length as I recall. If it is a different dimension, then the brake shoes would be riding on the cams at a different point changing the distance from the shoe to the drum. I have a 68 T120R and I have a lot more threads showing when my rod is properly adjusted. But given 68 was the first year for the 8" TLS set up, the cam levers are different than a 70.
Just measured the cable. The outer part is 42". I looked up the part on ebay and they have it at outer length at 39 3/8.
The length of the outer on its own isn't that important, it's the comparison with the inner length that's more important.
As I advised above, in online images of '68 Triumphs, look at the cable routing; do the same at images of '70 Triumphs. Note the completely different routing; if the cable routing on your bike looks more like a '68, a '68 cable inner is much longer in comparison to the cable outer. Also post a picture of the right-hand side of your bikes forks and wheel?
If you haven't done it already, you might want a second person to help you check the adjustment the brake arms link rod. I disconnect one end of the link rod from one brake arm; one person uses two wrenches (one on each nut) to pull both shoes against the drum at the same time, second person adjusts the the link rod so its ends are the same distance apart as the ends of the brake arms; reconnect link rod and tighten locknut.
Wally, I would be trying first what Stuart has suggested, getting the two shoes to touch the drum at the same time is vitally important, then work from there. I have came across a spongy front brake on a modern trials bike once where it supposedly couldn't be sorted, turned out that the cable had snagged on something and had got the wire coil sheath stretched so that when the brake was applied the outer sheath compressed first before the brake was applied, a new cable sorted it out. Check your own cable for damage, it is not always evident though.
[quote=Wally Balden]Just measured the cable. The outer part is 42". I looked up the part on ebay and they have it at outer length at 39 3/8.
I checked 2 choices with google (no eBay) and they were 36 & 36 3/4" outer, 45 & 44 7/8" inner. So 9 & 8 1/8" free lengths. (P/N 60-2076). Then e-bay, 2 with measurements were 38" outers and 46 & 46 1/2" inners (8 & 8 1/2" free length). So who knows? How much free length do you have? Also, did you have the shoes off, for clean-up, or replacement?
One last question. I have a brake now - wheel spins and when brake is applied the wheel stops. I know how to adjust at the lever and also at the adjuster on the cable. My question - when I pull the lever it stops the front wheel, however, it releases to a point - not all the way. The wheel still stays locked unless i manually push the lever back to its original point. I know there should be some free play but it does not want to return to the original position. Am I missing an adjustment?
Have you sorted out the arm length between the 2 cams, also have you took the brakeplate off and greased the shoe feet, cam shafts, checked the shoe springs are in place and are not stretched and weakened.
I have played with the arm length between the 2 cams. Not sure if I am making better or worse as I adjust. I have not taken the wheel off yet - trying to avoid that if possible. Probably a good idea. Most of the components were new - shoes, springs, etc.