Very ODD front brake challenge...

(2005 Triumph T100, combination)
The front brake pads were VERY low, so a new set purchased from a Triumph dealer in a Triumph box = authentic parts?.
Old pads removed OK
Calliper, springs, pin etc. cleaned up OK
Double brake pistons (in single calliper) cleaned up OK
Copper grease added OK
New brake pads fitted OK
Reassembly went as planned = OK
Result = NO FRONT BRAKE (at all)
No pressure at the brake leaver.
Air in system? = Checked master cylinder = working fine, Checked for air = NONE found (various methods inc. proper brake bleeding kit etc.)
Check unit re-fitted correctly = YES (I think)
HOWEVER!!!! If I undo the calliper to forks bolts (x2) just one turn each, I have PERFECT, solid brakes.
If I do the calliper to fork brake bolts up tight (x2) = NO brake at all.
WTF!!!!
Any ideas?
I am sure it must be something simple, but what?
Thanks in advance for any help
Chess
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UPDATE 1. (still NOT resolved)
With the OLD pads back in, the brake again works as it did, i.e. perfectly.
With just the new off-side pad in and the old one on the nearside, the brakes work 100%
With just the new near-side pad in and the old one on the offside, the brakes do NOT work at all.
Just in case the new pads were a tad too thick, I ground-off (FLAT!) about 1 mm from each pad = No change, not fixed.
As the calliper on this set-up (leading edge front combo forks), the calliper is fitted with the bleed nipple pointing so slightly downward, not upward as it was designed for, SO, just in case a bubble of air was stuck in there, I re-bleed the brake with the calliper off the bike facing upwards = NO air bleed out, no improvement when re-tested.
Conclusion, so far, Could still be that the new pads are too thick? (5% confidence), or there could still be air in the system? (50% still possible).

 

Thanks for the reply, however, yes I have done loads of other tests to try to identify what's going on.
One bolt at a time, less tight, more tight, etc. = I can fine tune the amount of brake I have by the level of tightness, (in the wrong direction), so that just a little tighter on the bolts, (or just one of them), etc. then brake gets worst by a fraction proportional to the level of tightness.

 

Hi. Thank You.
It looks like it is the new near side pad that is causing the issue. = YES and NO. Logically, YES, my experiments do appear to point to the near side pad as a focal point, but this challenge is proving illogical (so far) and the new pad is IDENTICAL to the old one in shape.
Yes, the same and it does slide freely. The faces look great and have now even been skimmed on a perfectly flat stone planishing machine by about 0.5 mm.
I have looked again and again, but so far can't see anything mechanically jamming that pad.
Yes, the new pads move freely with the calliper off the fork (work PERFECTLY off the mount).
Note: It's NOT a standard fork as this bike is a combo and has Leading Link forks.
I also can't see how the new pads can be too thick but I do think I could circumnavigate the problem (without ever getting to the bottom of it), if I were to find and fit slightly worm pads, say =25% used.
Luckily, to keep things simple I did not have to have the wheel off so that assembly has not yet been touched.

 

HI.
When fully tightened up, YES the brake leaver comes right back to the bar very easily with NO resistance at all.
NO, when fully tightened up, pumping the brake leaver, even 30+ times has NO effect.
Note: Following another persons suggestion, (even though I had little faith in it), I pumped the leaver 20 times and held it in with a bundgy last night and left it held in all night = no change.
YES, I will post a resolution when I have one.
Thanks again.

 

Hi.
Yes, at the mo. I think it would, however as it's my other half's bike and she has a chop and I have a Harley, it is not urgent and I plan to put in as much effort as required to resolve it this week, even if I have to take it to my local professional (Steve Pipers) who I have EVERY confidence in and who is also attempting to help me with advice and suggestions. He is convinced it's related to way the calliper is fitted (NOT the normal fully upright) which could cause air to be trapped.
The pads cost Kazzy £33 inc. from a Triumph dealer. IF it was the ONLY way, then we would try less skimming on a spare pair until we identified the opium thickness to start with, could be just -5% or so? I don't expect to have to go that route.

 

No, that was from Steve Piper, my local professional. He said he has found owners with custom bikes that have the calliper located such that it is not upright as designed and he resolves the issue by bleeding it off the bike.
I did try that this morning without success, but will try it harder again tomorrow.

 

hi.
Logically I agree with you, as NONE of the hydraulics were disturbed when first the new pads were fitted, they were only later disturbed in the hope of resolving the unexpected 'new' problem.
So, yes, I will try it as an experiment tomorrow (fitting shims or washers), however the previous (VERY experienced) owner has not given any reason not to use standard pads, and we spoke on this yesterday (but not that specific point), he did give many possible (standard) suggestions but none worked and most had already been tried.
Thank You again.

 

We have only had the bike a few months, so have no idea how or when the custom arrangement was made. However as we were given the removed/spare standard front end parts, (stanchions, forks etc.), from the bike before the Leading Link system was fitted, the calliper is from the standard donor bike, i.e. a 2005 T100. At the time, the pads may well have been part worn and still good enough to re-fit?
Regards Chess

 

YES, I will defo try it, however, I do see the logic on how the act of bleeding a calliper when it is not fully upright could make it difficult as the last bit of air would be in the body above the bleed nipple. I also agree, that if you were able to get all the air out, then the system should work in any orientation.
Being so simple, your suggestion will be the first one I try in the morning.
Thanks, tomorrow will give new information and results.

 

UPDATE (A solution is found!)
OK, this may not be the definitive solution or correct conclusion, however it works.
A good friend of mine who lives locally, Derek Hawkins, came round to help take on the challenge as he had a few ideas to trial.
We worked through a number of suggestions that you guys had make, just in case, but none solved the problem.
Working with the 'fit extra spacer washers to the mounting bolts' suggestion, we ended up trying different combinations of wash thickness's mixing and matching the front bolt and back bolt.
Various tests DID have an effect! but not a final solution.
Still scratching our heads, Derek took a look at the old pads and noticed that the old pads had not worn flat. They had worn at a significant angle, wearing down to the metal at one end and leaving about 1mm of pad at the other. Not only that, but the wear on each pad was reversed, so that one was totally worn out at the front, while the other was equally worn out at the back. He then concluded from that, that the assembly has been and still was attempting to work at an angle to the disk.
So, with that in mind, we started a long series of experiments wedging various thickness washers behind the front and back mounting bolts. After many trials we finally found a perfect solution.
With a 1 mm washer half fitted (acting as a wedge) to the back bolt, the calliper wash held firm and the brake worked perfectly. (and should get even better once the pads are worn in a bit).
= Job DONE...(well not quite).
THANK YOU all for your help and suggestions, I was overwhelmed by how many people too the trouble to offer help and advice. A special THANK YOU to Derek Hawkins for his help.
What next. If the assembly never has to come of the bike again, then all is well = finished, however as that is unlikely, unless I am the person doing the work or the 'half' wash is noticed, the next owner will have exactly the same problem all over again. So the long-term plan is to get hold of a 'spare' calliper mounting bracket/cradle and have it engineered to mirror the required angle.