Harley Davidson V-Rod Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
92 Posts
Discussion Starter · #1 ·
I'm having trouble bleeding the ABS rear brake on my NRS. I believe the problem is that both the caliper and mid control master cylinder are way below the ABS unit. I vac bled line about 5 times, even activated ABS on test rides in between bleeds braking on rough road and felt ABS kick in. Pedal still feel spongy.

I think air is trapped high near ABS and that the mytivac cant pull it through or passed ABS? I'm thinking of trying pushing the fluid with a syringe from the caliper to the ABS and bleeding out of the cracked open banjo bolt on the ABS unit then closed after fluid is flowing, This would be followed on the other side of the ABS unit pushing fluid from reservoir
up to the ABS unit and cracking that banjo bolt until fluid flows.

After that do a regular vac bleed to get remaining air out. Thoughts or better ideas? Thanks in advance.
 

·
VRSC est -03
Joined
·
3,095 Posts
1. Brake pads new? May have to be seated in.

2. Could this be of help?
 

·
Registered
Joined
·
81 Posts
I'm having a similar issue. I have the app and ODBII interface to activate my ABS, so I didn't have to go out and slam on the brakes.

I have the stock forward controls on my 13 NRS. I bled the front brakes and rear brakes. Activated both ABS and did another bleed. Front lever was spongy the very first pull, then was fine. My rear brake howver stays spongy. I also vacuum bled.

When I get back from vacation, I'm goin to bleed the rear brakes again, and this time I'll do the old manual pump the brake and hold, open bleeder, close bleeder, repeat. I'll see if that helps.
 

·
Registered
Joined
·
92 Posts
Discussion Starter · #4 ·
Still no progress on this.

Took it to the Harley dealer for the current brake fluid flush recall figuring they can also flush the fluid and put it on the digitool scan thinga-ma-bob that activates the ABS solenoids. They told me that they did everything required for the flush but the brakes are still spongy and now they have to start charging for diagnosis. They could not tell me what they think is the problem and @ $160/hr I wasnt going to let them keeping guessing at the problem.

Brought it home and ran another bottle through with Mitytech vac bleed tool. Rear end jacked high to help air move to caliper. No change and no air bubble at all and I see the fluid moving through the bleed tubing.

Bought a large sryinge and pushed fluid through from the caliper, and bled from the banjo bolts on the ABS unit. Pushed the syringe plunger cracked the banjo open and then closed a few times. Then pushed more through into the reservior.

In addition I ran another bottle through using the old fashioned pump the pedal and crack the bleeder. No bubbles. Still no change.

The ABS was working fine with the forwards and I don't get the ABS light or codes. I believe the ECU and HCU are fine. The ABS activates when I jam on the rear brakes (hear the unit cycling and feel the pedal vibrating and pushing the pedal up into my foot). The brake does stop me however the force and length of pedal travel is way to much. I'm not locking my self into this one thought but it gives the classic feel of air in the system.

I'm open to ANY suggestion including kicking the bike off the jiffy stand! PS - I rebuilt the Master with the Harley kit (which is nothing more than the plunger rod that pushes the fluid).
 

·
Registered
Joined
·
92 Posts
Discussion Starter · #5 ·
Relsolve to this post - After trying everything the only two things that were replaced were the Master cylinder and the line from the cylinder to the HCU. I guessed and replaced the custom (rubber) line I had made and ordered the Harley part. That was it! The mids work fine now.
 
1 - 5 of 5 Posts
Top