VF500 Interceptor -- No front brake pressure

Thanks Guys. will try these when im back home. I have a set of steel braided lines on the way. at this point im certain its an air bubble issue.

 

just did my 83 had same problem , only time I got any feel in myclutch was to fill a brake fluid vacuum tank and carefully blow the fluid back into the master cylinder ,only had feel a couple pulls, took apart piston seals were a hair too small wrong rebuild kit

 

Haven't gotten back to this yet. I got a new bleeder, so will try that as well, but may need to use a Syringe to back feed it

 

Still no luck here. Its now isolated to the left front calliper. If I Pinch the line immediately above the banjo connector on that side I have a full firm lever. (yes I know the pitfalls of pinching the line, but needs must)
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Ive pulled an additional 2 litres (4 containers) of brake fluid through it with the mityvac and by the traditional pump and release method and still no change, lever still goest straight to the bar.

I bought a syringe to do a reverse bleed finally got fluid to go backwards from the calliper to the master cylinder. no difference.

I pushed the calliper pistons further in the bores and put a piece of metal in, instead of the brake rotor, and it was a bit better but not perfect

so far ive:

-changed the master cylinder (taken of another bike that was fully functional)
- master cylinder tested good
-changed both callipers (taken off a bike that was fully functional)
-changed the lines (taken of another bike that was full functional)
-put 2 litres of fluid through it
-pulled the calliper off and rotated it to see if I could dislodge and air bubbles
tapped the calliper and the lines to dislodge bubbles
-tied the lever back for a week
- reverse bleed the calliper

 

LOL - Disconnect the lines from the Master Cylinder (MC).
With fluid in the MC, & finger over the end, pull the lever - do you get pressure?

If Not rebuild it

Assuming you have pressure, then the air is in your lines or callipers.

After RECONNECTING the lines to the master cylinder reverse bleed using the syringe. As you push in the syringe - pull the lever. You should see bubbles in the MC cap. DO NOT OVERFILL the MC cap. This will push the air out the top.. You should feel the lever improve..

 

Yes, the master is good, rock hard with finger over the hole, I tested it when I swapped it out.

its rock hard with the line pinched at the left calliper too - so I know there is air in that specific calliper or the calliper is F'd. Ive swapped the callipers once already. and bled them 10 ways til Tuesday.

I just reverse bled it with the syringe -- no difference -- put 3 master cylinder loads of fluid thru it via reverse bleed -- nada.

I have never ever had issues like this bleeding brakes.

 

Again, fairly easy, So its not the master or the right calliper. Change to the Mityvac, lift the left calliper so it is higher than the MC & suck it out - lol

 

swapped the left calliper again (3rd different one) and different bleed screw and Im starting to get some pressure now.

 

It sounds like it could be the pistons retracting when you release the lever. I have seen this before. I had similar symptoms with some GS1000 calipers years ago. You should watch the pistons as you pull the lever and watch what happens when you release. If the pistons move back then most of the the lever travel is being wasted pushing them out again. I fixed it by renewing the caliper (piston) seals.

 

thanks for all the replies guys !!

very helpful

Problem is now sorted - swapped out the left calliper again, all good !!

 

Sorry to dredge up an old fossil of thread, but I am now having the EXACT same problem with my VF500F.

So is it the consensus of the group that the it is the calipers at fault?

I just overhauled the MC with a K&L kit and now have little or no pressure, even with a vacuum bleeder. I thought this was going to be an easy job but after reading the above thread I think I am screwed.

 

Various other ways of dealing with this.

Reverse bleeding - attaching a syringe to the calliper and pushing fluid into the calliper.
Master Cylinder Bleeding - crack the hose bolt at the M/C WHILST pulling in the lever.
Tying up the lever to the bars overnight. - limited success with this !

 

Also are you positive that you inserted the M/C kit correctly - On on of my bikes the orientation of one of the rubbers makes all the difference to not working or perfect..

 

Id say not necessarily the Caliper. If you rebuilt the Master Cyl, Id say its just Air in the system. What I found is these brakes are a bugger to bleed properly. I used a MightVac, a Srynge to reverse bleed it, conventional bleeding at the caliber, and bleeding at the M/C.

 

I have been using a vacuum all day and cracking banjo bolts and no success.

I have not cracked the banjo bolts at the manifold on the fork however. But I have seen absolutely no improvement no matter what I have done so far. I can feel the calipers moving slightly however when I pump the lever.

Going to let it sit overnight and see what happens.

I work on bicycle hydraulic brakes all the time (you want to talk about a Pain In the Ass!!!) and they (Shimano and SRAM) have a bleeding kit that relies on syringes to reverse bleed the system.

If I get a syringe, how do I actually hook it up to the caliper? I am at a loss here.

 

I checked the piston before I put it in. The rubber cup was already installed. I did not check the orientation of the cup. I suppose it could have been installed backwards. But I am getting fluid flow from the MC as I can feel the caliper pistons actually move a bit when I work the lever.

 

Not an ideal thing to do but...... if you clamp off the brake line(s) at the caliber (s) do you then get any better feel ?

My issue was air in the caliber and if I clamped off the brake line on one caliber my lever felt firm. I was able to isolate the offending caliber but....I didi run the risk of damaging the brake lines. I dont recommend this, im just saying I did it.

 

I was just out in the garage looking to do just that. I hate to damage the hose but I am very curious to test out this theory.

 

Just be very careful Jim, dont want to have one of those hoses fail on you. you dont need much pressure to clamp them and inspect carefully after, splitting a hose while your riding wouldn't be good.

I needed up changing my lines, as they were original and not in great shape anyway.