Nissin front brake bleed ISSUES - AGAIN !! FFS

Same old story guys, I just cannot get a good bleed on the front brakes of the VF1000R. As a back ground, the brakes were perfect before I tore it down.

Here's what I have done:

-Disassembled and cleaned the callipers, silicone rubber grease on the seals before I put the pistons back in, pistons were spotless.
-New stainless braided lines
-Reverse bled the callipers in stages 1) to the top of each calliper line, 2) then to the top off the MC line, then 3) in to the MC
-I used the method to modulate the lever while the syringe was pushing fluid up, until there were no more bubbles coming up in there MC. Lever was moving very freely as you'd expect.

Then I used the Mighty Vac speed bleeder on the left side Calliper. After that, the lever would barely move it was rock solid, even when I cracked a bleeder nipple it too 2 hands and all my strength to get the lever to move. kept working the lever and spinning the front wheel, it would take a few seconds for the brake callipers to release fully once the lever was released. Eventually, that got sorted out and the lever stated moving freely, but spongy as I would expect prior to a proper bleed.

Then I reverted to the traditional bleed method, got some more bubbles out and kept at that until I got no more bubbles.

Now my lever is still really soft on the first pull, then gets really stiff on the second and subsequent pulls.

This is EXACTLY the same issue I have had on the last set of Nissin brakes - which I never resolved (bike got sold with full disclosure before I got to fixing it).

Im at a loss for why this is happening. I dont expect pistons are hanging up, im using Bellray DOT4 fluid, I dont see any leaks.

I suspect air still trapped some place. Ill unbolt the callipers from the brackets and move them around a bit maybe dislodge any air and tie the lever back next.


EDIT: I will also say that the initial pull on the lever while spongy its still harder to pull than it should be. example, I pulled of the right calliper, pushed the pistons back in and re mounted the calliper. You'd think the initial pulls on the lever to re seat the pads and pistons to take up the slack would be super easy, but it was sloooow and stiff. Almost like there is an obstruction somewhere.

I did the same on the left side and it was somewhat easier than the right.

I fucking hate Nissin front brakes !

 

Update:

took callipers off, moved them , tapped them - no more air

I put the bike back on the head stock stand and I can confirm 100% that it takes 2 seconds for the brakes to let go of the disc's after the lever is released, for some reason something isnt allowing the pistons to retract. So is that a MC issue (that didnt exist before) or something else? I didnt touch the MC in the rebuild as it was working fine.

It does seem harder to pull the lever when I crack the bleed nipple on the right side calliper. and it did take a harder pull on the lever to take up the slack when I pushed the pistons in on the right calliper.

I may have to look closely at the right side brake line and see if I have an issue with the new line. maybe ill crack the banjo on the right calliper first and see how that feels

 

Straycat,
Is it possibly collapsed brake lines? I've seen some really strange things happen when brake lines get old and fail internally. If you open the bleeder on either caliper it should be very easy to pull the lever (and squirt brake fluid everywhere).
Good luck

 

"-New stainless braided lines"

 

@mikenmo Well, yes it is possible it seems. I kept going back to the fact that the right side calliper was reacting different to the left.

I cracked the bleeder on the left and fluid flies and lever shoots to the bar with ease, on the right side, just a dribble and the lever comes back veeeeerrrryyyy slowly so
I swapped out the new line on the right side with the old one and Bingo, the lever is now behaving like it should and the brake callipers are no longer locking up. Seems my new stainless lines are shite, and one of them is obstructed not allowing the fluid to return or flow as it should. Ill be contacting the ebay seller for refund/replacement.

lever isnt quite what I want re firmness yet, but its better. No point in messing more until I get a new line for the right side.

all day doing this.

 

Yes, I read that. It still sounds like a brake line issue to me. Just trying to be helpful where I can. Sorry.

 

you were right mikemo, see my last post ! thank you !

 

Whoa. Cool you found it.

mikemo FTW.

 

I can blow through the line , but no idea how much "flow" I should get, blowing isnt very scientific , I just decided to see if it was obviously obstructed but its not.

They're Galfer lines, I used the oem Honda banjo bolts instead of the ones that came with it, so im assuming that wouldn't be an issue causing the holes in the banjo fitting to not line up with the holes in the Banjo bolt.

The one I had issues with was the one on the right side of the splitter that mates up with the MC line and banjo fitting on the same longer 2 hole bolt. I figure thee things should be fairly standard in size you'd think.

 

Not necessarily. Throw a caliper on the fittings. I recently ran into this, but didn't get as far as bleeding. I had to use a slightly different banjo bolt to make me feel better about proceeding.

 

Hmmm....maybe ill re try with galfer supplied banjo bolts tmo. spent a whole day on this , whats another day when your retired eh. calliper banjo bolts are ok, its that 2 banjo bolt im wondering about. the new banjo fittings ones did measure a wee bit smaller with the calipers. maybe just enough to fuck me up.

 

Is the other tiny hole in the master free of gunk and not clogged? Hard to explain but it's the little pinhole under the aluminum guard around the center of the reservoir.....I had a similar issue with the VF in that I could compress the piston in the MC but it wouldn't freely return because that vent hole, return hole, whatever you wanna call it was very slightly clogged.....just a thought!

 

Yeah, sucks, I see you've found the problem... Just a comment, I am not a fan of vacuum bleeders, mixed results for me. After reverse fill/bleed, I think best to bleed the old fashioned way...

 

Yea, the little holes are both clear. the brakes are working decent now, needs a bit more bleeding, but I found the issue. its either a bad brake line or using the oem bolts instead of the Galfer bolts.

 

Yea, ive had mixed results as well. I used the vacuums bleeder on the clutch today and it was bled and perfect in a heartbeat. Front brakes, not so much.

 

We will see what tomorrow brings. hopefully more success than today.

 

Ok guys, all fixed and all good.

I put the new brake line back on with the new Galfer banjo bolts instead of OEM bolts and its all good. Bled with no issues !!

Lesson learned here -- Always use the supplied Banjo Bolts with new lines. OEM Honda may not be compatible with aftermarket stuff !