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General Category => Modifications => Topic started by: rlucas on July 05, 2018, 10:52:22 AM

Title: Rear Brake Mods?
Post by: rlucas on July 05, 2018, 10:52:22 AM
I've just upgraded the '86 to a set of blue spots (actually, they're the silver ones), with a corresponding master cylinder. Has anyone done any mods to the rear caliper, apart from related swingarm swaps? I've bled the system and ordered a fresh set of HH+ pads for the rear, but it feels kinda weak and unresponsive now in comparison with the new front setup.
Title: Re: Rear Brake Mods?
Post by: FJ_Hooligan on July 05, 2018, 12:55:46 PM
Quote from: rlucas on July 05, 2018, 10:52:22 AM
I've bled the system and ordered a fresh set of HH+ pads for the rear, but it feels kinda weak and unresponsive now in comparison with the new front setup.

Which might be the more desirable feel for a rear brake.

The HH pads will probably be the only upgrade you need.
Title: Re: Rear Brake Mods?
Post by: red on July 05, 2018, 12:58:39 PM
Quote from: rlucas on July 05, 2018, 10:52:22 AMI've just upgraded the '86 to a set of blue spots (actually, they're the silver ones), with a corresponding master cylinder. Has anyone done any mods to the rear caliper, apart from related swingarm swaps? I've bled the system and ordered a fresh set of HH+ pads for the rear, but it feels kinda weak and unresponsive now in comparison with the new front setup.
Rlucas,

Is the brake pedal now solid, and right up top?  I found with mine that the usual bleeding process was not all that effective.  I made a small change; I pushed down the pedal normally, but sidestepped the pedal to let the pedal spring back up as fast as it would go each time, no load.  That trick moved much more fluid in the brake system, and I got a "new-bike" solid rear brake pedal when finished.  You need to move a lot of brake fluid if you have ABS brakes, before you will get all new fluid in the system..

Other than that:

1. You might want to clean and lube the brake lever pivot, so there is less friction in applying brake pressure.  It can help.  I'd use the best moly grease, there.
2. Replace rubber brake hoses with new braided stainless steel hoses.  Any decent hydraulics shop should be able to make what you need locally, or try your luck on-line.
3. If you have a high point in your rear brake system, investigate the use of a banjo bolt that has a bleeder-screw built in.  These bleeder-banjo bolts cost about US$15~20 each, but some places charge far more.  Use fresh brake-line washers, if you replace a banjo bolt.
Title: Re: Rear Brake Mods?
Post by: rlucas on July 05, 2018, 02:11:51 PM
Quote from: red on July 05, 2018, 12:58:39 PM
1. You might want to clean and lube the brake lever pivot, so there is less friction in applying brake pressure.  It can help.  I'd use the best moly grease, there.
2. Replace rubber brake hoses with new braided stainless steel hoses.  Any decent hydraulics shop should be able to make what you need locally, or try your luck on-line.
3. If you have a high point in your rear brake system, investigate the use of a banjo bolt that has a bleeder-screw built in.  These bleeder-banjo bolts cost about US$15~20 each, but some places charge far more.  Use fresh brake-line washers, if you replace a banjo bolt.

Everything's clean and lubed. The lines were replaced, front and rear, with stainless a long time ago when I upgraded the original '86 front end to an '89. No high points in the line. I will try the bleeding method you mentioned, though.

Quote from: FJ_Hooligan on July 05, 2018, 12:55:46 PM
Quote from: rlucas on July 05, 2018, 10:52:22 AM
I've bled the system and ordered a fresh set of HH+ pads for the rear, but it feels kinda weak and unresponsive now in comparison with the new front setup.
Which might be the more desirable feel for a rear brake.

Agreed - that thought had occurred to me, but the disparity in effort required just seems excessive. The HH+ pads should be here Monday, so I'm hoping that helps.

rossi
Title: Re: Rear Brake Mods?
Post by: red on July 05, 2018, 08:00:51 PM
Quote from: rlucas on July 05, 2018, 02:11:51 PMAgreed - that thought had occurred to me, but the disparity in effort required just seems excessive. The HH+ pads should be here Monday, so I'm hoping that helps.
rossi
Rossi,

At the risk of being obvious, I'd suggest a healthy shot (or two) of brake cleaner and toweling on the disk rotor, between removing the old brake pads and installing the new brake pads.  If your disk rotor is perforated, clean inside each hole as well.  Just a thought . . .   8)
.
Title: Re: Rear Brake Mods?
Post by: Bones on July 06, 2018, 03:57:28 AM
What back wheel have you got Rossi, the brake on the standard one I thought worked well no matter what pads were in it, had no trouble at all locking the wheel. The gixxer wheel on the other hand is pitiful, I'm putting it down to the rotor being smaller so it takes a lot more effort. I've got sintered pads in mine at the moment and It is pissweak to say the least.
Title: Re: Rear Brake Mods?
Post by: rlucas on July 06, 2018, 06:38:10 AM
Quote from: Bones on July 06, 2018, 03:57:28 AM
What back wheel have you got Rossi, the brake on the standard one I thought worked well no matter what pads were in it, had no trouble at all locking the wheel.

FZR rear wheel (IIRC...it's been a long time) with the standard FJ rear caliper.
Title: Re: Rear Brake Mods?
Post by: red on July 06, 2018, 09:59:19 AM
For my FJ, I have found that locking the rear wheel has a lot more to do with the tire than the brake.  After two incidents of heavy braking (not panic braking), with the rear wheel locked, I got better tires (Pirelli Sport Demons).  The Pirelli can brake much harder without lockup, but if I try hard enough, I can still lock the rear wheel on purpose.  My brakes are well maintained, sure, but they are factory stock, non-ABS.

My $.02 worth.
.
Title: Re: Rear Brake Mods?
Post by: oldktmdude on July 06, 2018, 05:46:18 PM
Quote from: rlucas on July 06, 2018, 06:38:10 AM
FZR rear wheel (IIRC...it's been a long time) with the standard FJ rear caliper.
That's the combination that I'm using with EBC HH pads and it works great. No trouble to lock up if required, some that have ridden my bike
comment  "that it's a bit too touchy."
  Regards, Pete.
Title: Re: Rear Brake Mods?
Post by: JOMPPA10 on July 20, 2018, 11:24:11 PM
Quote from: rlucas on July 05, 2018, 10:52:22 AM
I've just upgraded the '86 to a set of blue spots (actually, they're the silver ones), with a corresponding master cylinder. Has anyone done any mods to the rear caliper, apart from related swingarm swaps? I've bled the system and ordered a fresh set of HH+ pads for the rear, but it feels kinda weak and unresponsive now in comparison with the new front setup.

they are weak i use suzuki caliber(17inc rear :flag_of_truce: underslug) but rear brakes are only for HARLEY users.
but you can use it better by shortening brakeline and using ss lines if you want
Title: Re: Rear Brake Mods?
Post by: rlucas on July 21, 2018, 08:04:18 AM
Thanks for the input, everyone. The change to HH+ pads on the rear seems to have given me the more balanced feel I was looking for. Now there's just one more brake problem...

The lever on the FZ6 master cylinder is silver and the one on the stock clutch lever is black. This offends my aesthetic sensibilities. They seem to want an arm and a leg for a used, matching FJR clutch master, and aircraft stripper won't touch the finish on the stock lever. Time to break out the Dremel... :smile:


rossi