one step forward, two steps back (again)...

I need to walk away from this project for awhile. over the years, I've wrenched on everything from volkswagen beetles to B1 bombers, but lately, this seems to be happening more often. seems like as soon as I get something completed, I have to get back in there for a re-do. latest - a couple weeks after the brake caliper rebuild on the Mk2, I spot a drop of brake fluid on the garage floor. two weeks and NOW it starts leaking - WTF - . looks like it's coming from the inboard-inner seal/piston. new rebuild kit and stainless pistons, and internal surfaces looked perfect. it's not like I haven't done caliper rebuilds before, and as careful as I was, well, it's just kind of depressing - . guess I need to get back in there for a look-see. ordered up a new rebuild kit - just in case. not looking for advice or anything, just venting.

Sometimes walking away and coming back fresh later is definitely the right thing to do...

The whole point of a can of beer in the fridge at all times

If you read my post in "Rebuilds" about the persistent oil drip on the Titanic, you'd know I sympathize. Who suspects a brand-new part or rebuilt component's new parts?

Fast Eddie said:

Sometimes walking away and coming back fresh later is definitely the right thing to do...

Click to expand...

,,,,,and venting!

As drilled into our heads at mechanics school"A new part is not necessarily a good part!"
Wrench on
Dave

I hear ya brother. I have probably 60 hours and $6000 invested in my Norton this year and it left me stranded while on the way to the only annual Brit Iron show in my area. Blown fuses, blown regulator, blown ignition, stuff that has worked perfectly for many years suddenly doesn't.

The good news is that the e-start works perfectly and there are no more oil leaks. Gotta look at the positive things, else you go nuts.

Yes it gets frustrating and no use getting angy with it the best thing is walk away, sit down over a few beers and think about it, a lot of new parts do fail they don't seem to be as good as the original parts these days, the best thing I ever done with my old 43 year old brakes was to bin them and replace with all new upgrade system, my life is more important than keeping original after my original front brakes let me down twice and I got hurt, could have been worst, I went for the full Grimica set up and looks way better on the bike, lot of options out there and as I say my life is more important than keeping thing original.

Ashley

Hi Joe, just throwing out some ideas.....so you did a caliper rebuild on the front disc set up as it is a Mark 2?
What did you rebuild, put new rubber rings around the pistons maybe, anything else?
the leak could be as simple as a loose connection at the brake fluid hose to caliper connection?
or do you see any brake fluid on the disc, having dripped from above to help find the source?
is it possible the fluid is coming down the line from the handle bar end or perhaps the nipple is not tightened enough from bleeding it?

1up3down said:

Hi Joe, just throwing out some ideas.....so you did a caliper rebuild on the front disc set up as it is a Mark 2?
What did you rebuild, put new rubber rings around the pistons maybe, anything else?
the leak could be as simple as a loose connection at the brake fluid hose to caliper connection?
or do you see any brake fluid on the disc, having dripped from above to help find the source?
is it possible the fluid is coming down the line from the handle bar end or perhaps the nipple is not tightened enough from bleeding it?

Click to expand...

correct, a Mk2. kind of simple internals - housing with two inner seals and two pistons, and an external plug w/ seal. no rings around the pistons. the rubber seals were in groves, internal to the caliper housing. I lube the rubber seals with brake fluid, installed the inner seal and push the inner piston. then installed the outer seal and piston. really kind of a easy rebuild. everything was spotless during assembly and couldn't feel any imperfections within the housing after cleaning. new stainless pistons - measured out (overall average) at 1.746 (new) vs. 1.747 (originals). the leak is definitely internal and not a hose connection - leaking down past the housing and the inner brake pad. fluid dripping down on to the rotor. kind of worried fluid has contaminated the new brake pads - . one thing i'll do when re-rebuilding, is swap the pistons from the inner to the outer side of the caliper. if the leak follows the pistons, I might have an issue with the pistons, if the problem stays on the inner side, I might have an issue with the caliper housing. slim chance, but then again, I might have just gotten a flawed seal, and the problem goes away with a new seal kit. the rebuild should go easy since I don't have to go thru an extensive cleaning process.

I seem to recall there was some asymmetry to the piston seals cross sectionally. Could it be these were wrong way around in the grooves?

Anyway, I had a heck of a time getting my mkii brakes sorted. Initially trouble with the sleeve mc, then I think it was more than ten days before it got fully bled. Tried all sorts of techniques but ultimately worked was flicking the brake lever rapidly 50+ times and suddenly seeingtiny bubbles come othe small hole in the MC. Been great for 7k miles since.

Tornado said:

I seem to recall there was some asymmetry to the piston seals cross sectionally. Could it be these were wrong way around in the grooves?

Anyway, I had a heck of a time getting my mkii brakes sorted. Initially trouble with the sleeve mc, then I think it was more than ten days before it got fully bled. Tried all sorts of techniques but ultimately worked was flicking the brake lever rapidly 50+ times and suddenly seeingtiny bubbles come othe small hole in the MC. Been great for 7k miles since.

Click to expand...

The seals can go in either way. It’s the machined grooves that are angled at the bottom giving the seals their lead. When I did my caliper there was a lot of hard crusty stuff in the grooves. I used a curved dental pick to remove it.
Cheers,

cliffa.

joe czech said:

I need to walk away from this project for awhile. over the years, I've wrenched on everything from volkswagen beetles to B1 bombers, but lately, this seems to be happening more often. seems like as soon as I get something completed, I have to get back in there for a re-do. latest - a couple weeks after the brake caliper rebuild on the Mk2, I spot a drop of brake fluid on the garage floor. two weeks and NOW it starts leaking - WTF - . looks like it's coming from the inboard-inner seal/piston. new rebuild kit and stainless pistons, and internal surfaces looked perfect. it's not like I haven't done caliper rebuilds before, and as careful as I was, well, it's just kind of depressing - . guess I need to get back in there for a look-see. ordered up a new rebuild kit - just in case. not looking for advice or anything, just venting.

Click to expand...

Doublecheck all pipe connections. I've had similar leaks that I was sure were coming from inside and in each case, they were either the bleed screw or the bundy pipe. I'm always worried about overtightening them and end up under tightening them!

maylar said:

I hear ya brother. I have probably 60 hours and $6000 invested in my Norton this year and it left me stranded while on the way to the only annual Brit Iron show in my area. Blown fuses, blown regulator, blown ignition, stuff that has worked perfectly for many years suddenly doesn't.

The good news is that the e-start works perfectly and there are no more oil leaks. Gotta look at the positive things, else you go nuts.

Click to expand...

Magneto anyone? Apologies. Just had to.