Rear Brake Super Soft After Wheel Removal & Brake Work

[durty3]

Hi All,
It has been a busy week on my bike--new tires front and back, cleaned the calipers (did NOT replace caliper seals) and bled the brakes.

I went with the Bridgestone BT-023 tires and am very excited to see how they feel. I cleaned the front calipers, pads and rotors are in good shape and bled the lines, feels great!

I aligned the rear wheel, chain slack is good and cleaned the rear caliper along with a bleed of the system.

QUESTION: now my rear brake pedal goes super low and feels soft. I don't think there is any air in the brake system and everything looks aligned properly. In the attached pictures you can see how far out the piston is, not sure why, as it retracted pretty easily for assembly. In the linked videos you can see how low the pedal goes as well as how much the caliper seems to deflect/move upon brake actuation.

I did not touch any of the adjustment points on the pedal or master cylinder, not sure what would cause this now after reassembly.

Video links:
https://youtu.be/Jq7I-NVvnJU
https://youtu.be/MFi8URBdFuk

Thanks for any input!

 

[FinalImpact]

Are you sure all of the wheel spacers are in the wheel?
And you saw the caliper bracket slide into the swing arm anti rotation lug?

Its big bump looking thing on the swing arm. The caliper mount has a grove. These fit slip and lock together preventing caliper rotation on the swing arm.

In the tech section stick are pictures... take a look there.

JM2C - all that grease is gonna hold a lot of dust...

 

[durty3]

Thanks FinalImpact!

I didn't see any spacers. The only thing that was loose when removing the wheel was the collars on either side--they are both back in (part #19 http://www.bikebandit.com/oem-parts/2004-yamaha-fz6-fz600ss/o/m145558#sch298798).

Yes, best I can tell the caliper bracket is properly seated on the anti rotation lug.

Not seeing pictures in a sticky post from the tech section, link possibly?

Thanks for the note on the grease. Everything was bone dry and now I agree I overgreased. I will wipe some off.

 

[TownsendsFJR1300]

Here's a pic of the brake bracket:



The piston sticking out is normal.

Looking at your video's, it appears you have a bunch of air in your system. That pedal should move no more
than an inch or so.

When you bled the system, the nipple was always closed when fluid wasn't coming out or the peddle
had pressure on it, correct?

We're you able to torque the axle down fully without any binding, wheel spins fine, no brake drag? Is the
aluminum brake bracket nice and tight, no movement (with the axle tight)?


If you did that correctly, pull the wheel off again and compare the wheel assembly, spacers, etc
piece by piece as you assemble.


Plus one on removing the excess grease. Brake cleaner is your friend!

 

[durty3]

Thanks Townsends!

After reading extensively on the forum before starting the project, I read about how you damaged the brake bracket once when it was improperly aligned--fairly certain I got it correctly positioned as it has no real movement and seems aligned. We did torque the axle, albeit without a torque wrench.

The wheel spins about half a turn, but doesn't feel like it's dragging--too few turns?

Besides the collar (part 19 I mentioned above) what spacers do you guys keep referring too?

I guess the easy thing to do is bleed a little more. I have bled a million cars and I did the front successfully, but entirely possible I screwed up on the back. Any trick or pitfall on bleeding the back I should know about?

Thanks for all of the help!

 

[Motogiro]

Remember that the pads must be replaced exactly as they came out so they mate correctly. I've never had a rear caliper off the bike where the rear brake didn't take a little rebraking in to get the feel back. There is also a fine dust that forms particles that increase the friction between the rotor face and the pad face. As you use the brake that dust rebuilds and the feel comes back. All off this is of course assuming the pad are back in their respective locations and are not contaminated with any oil or grease.

 

[TownsendsFJR1300]

Just to be clear, I never bent that bracket, another member did, myself and Finalimpact helped him figure it out..

Both #19 spacer are the only spacers, on the exterior that would be an issue if forgotten, see pic:



There are some spacers inside (visable on the pic, #7) in the middle of the wheel, (one larger needle bearing to be exact).

Spacers #19's should be the only ones you would have disturbed with the wheel off unless you went deeper.

Making SURE that brake bracket is properly installed is CRITICAL. Some crawling on the ground will easily verify its in the slot..That the outside #19's are installed with the smaller end in the seals of course is critical(shouldn't even be able to assembly the wrong way)

Your bleeding procedures, is that strictly pumping the lever, hold and release the caliper valve? The procedure should work but if not,
a vacuum tool, you might be more successful.

One thing you may also try for bleeding, is to put a spacer in-between the piston and caliper body to keep it in. Get a helper and bleed BUT
hold the caliper higher making it easier to bleed any air that may be in the line (where the line rises up some, above the swing arm).

You really shouldn't have any air in the system from what you've earlier described. Its either something missing/not assembled correctly Or air in the system...

And lastly, the rubber inside the brake fluid reservoir cap, will appear there's plenty of fluid in there if its extended out. Keeping a VISUAL on the fluid level there is critical or you suck air and get to do a" do-over"


I recently rebuilt my rear caliper, new seals (same as yours) BUT I kept the caliper above the master cylinder to keep that from draining.
I didn't even disconnect the line. Cleaned and replaced the seal, re-installed everything. I used a Mity vac and it bleed out pretty quick
(much faster than the front and of course, the MC never went dry)

 

[TownsendsFJR1300]

Remember that the pads must be replaced exactly as they came out so they mate correctly. I've never had a rear caliper off the bike where the rear brake didn't take a little rebraking in to get the feel back. There is also a fine dust that forms particles that increase the friction between the rotor face and the pad face. As you use the brake that dust rebuilds and the feel comes back. All off this is of course assuming the pad are back in their respective locations and are not contaminated with any oil or grease.

For the rear Cliff, with that alignment pin visible from the back, the pads can only go back in one way. Now there are SS anti rattle "springs" around the pads that should be in place. Plus 1 on everything else thou!

 

[durty3]

Thanks for all the replies! Townsend, hope I didn't sound like a jerk in saying you damaged the bracket. I read so many threads that I no doubt mixed things up, it just stuck in my head when I was in the garage to be careful with lining that part up!

After reviewing everything shared, I am leaning towards further bleeding. I will take the caliper off and reinspect everything, but I am fairly certain it is all correct. While it is off, I will tap it gently and bleed it with the bleeder at the highest point.

If I am lucky, I can get to the bike tomorrow after work. Sit tight and I will be back with an update as quick as I can!

 

[FinalImpact]

Something is wrong tho. Your caliper tweaks sideways as if the rear is locked?

It is possible to assemble it correctly but if the floating pin has too much grease in it, it may be hydraulicly locked which explains why its not floating parallel to the disc.

Any chance you packed the cavity full of grease? The one on the rear w the boot/belows!

 

[TownsendsFJR1300]

Something is wrong tho. Your caliper tweaks sideways as if the rear is locked?

It is possible to assemble it correctly but if the floating pin has too much grease in it, it may be hydraulicly locked which explains why its not floating parallel to the disc.

Any chance you packed the cavity full of grease? The one on the rear w the boot/belows!

To add to this (very possible), make sure the bolt goes in fully a couple of times.

If that still doesn't allow proper pedal movement, remove the caliper from the bracket (do NOT disconnect the brake line).
Put something (piece of wood maybe) in between the piston and caliper(eliminating any potential issues with the rear wheel).

Now try bleeding the caliper, WITH THE WOOD, (at the normal height) and see if you can get the pedal back to normal.
If you can, you know there's something not right with the wheel assembly / elsewhere.. The brake itself is fine-rule it out..


Just a side note, You are using brake specific grease correct?

 

[TownsendsFJR1300]

Re the brake assembly itself:




Is sleeve #7 still there, and anti rattle springs #8 and un-numbered spring (next to boot #11) are both correctly installed?



Admin, pic is from Partzilla parts fisch

 

[durty3]

Thanks for all the advice everyone, spent an hour with the bike tonight!

1) I bled the brake again, this time, with the caliper on a piece of wood and much higher than the master, but that didn't make any difference in the pedal feeling. There really wasn't any reason why air would have been introduced to the system (unless I screwed up the bleeding). So I kept looking...
2) I reviewed the parts fisch and every part is there and appears to be in the correct space. I cleaned up all slides with brake cleaner and applied the tiniest bit of synthetic brake grease!
3) What you will see in the videos below is that the wheel spins smoothly without the caliper in place. It appears that the floating caliper isn't floating too well. Maybe I need a seal kit for the caliper?
4) Even if the caliper floats better, I still don't see why my pedal is going to the floor!

Videos links:
https://youtu.be/zYfqH2lthqA
https://youtu.be/fsG9QBz9tQI

Lots of pictures below, hopefully somebody sees something I do not!








Thanks so much for everybody's help and input, you guys are great!

 

[Motogiro]

If you're getting a lot of blowby on the master cylinder piston it would produce lot's of pedal travel with little braking pressure.. It also does sound like the piston in the caliper is not retracting properly. Maybe the problem is in the master cylinder....

 

[TownsendsFJR1300]

I noticed you didn't remove the pads for the pic's (maybe convenience).

First, the wheel rotation/assembly looks good tightened down.

Second, with the caliper on, WAY TOO MUCH DRAG-your issue is there..


Question of the hour, are you installing the pads first, ALONE, in the main aluminum bracket, THEN sliding the
caliper over them, THEN the retainer pin/bolts? The pads are aligned in that bracket and its CRITICAL THEIR LINED UP PROPERLY.

I don't think it would go together any other way but I have to ask..

Even if you needed a caliper seal kit, that would help any dragging HOWEVER, as it sits, the brake lever should still pump up and get hard with approx 1" of movement, even if the piston was frozen.

Please address the pad installation question.

Do you have a shop manual???

Some more options after you address / check the pad's..

 

[FinalImpact]

Thanks for all the advice everyone, spent an hour with the bike tonight!

1) I bled the brake again, this time, with the caliper on a piece of wood and much higher than the master, but that didn't make any difference in the pedal feeling. There really wasn't any reason why air would have been introduced to the system (unless I screwed up the bleeding). So I kept looking...
2) I reviewed the parts fisch and every part is there and appears to be in the correct space. I cleaned up all slides with brake cleaner and applied the tiniest bit of synthetic brake grease!
3) What you will see in the videos below is that the wheel spins smoothly without the caliper in place. It appears that the floating caliper isn't floating too well. Maybe I need a seal kit for the caliper?
4) Even if the caliper floats better, I still don't see why my pedal is going to the floor!

Videos links:
https://youtu.be/zYfqH2lthqA
https://youtu.be/fsG9QBz9tQI

Lots of pictures below, hopefully somebody sees something I do not!

View attachment 66575
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View attachment 66581

Thanks so much for everybody's help and input, you guys are great!

Did you remove the grease from the slides? The grease deep in the bottom where the pin enters?

With the pads out, install the caliper to the bracket. Tighten the pivot bolt. The piston should be parallel to the disc. The caliper should center over the disc (piston to pad stop), and last but not least, the caliper assembly should easily slide back and forth AND remain parallel to disc.
Do this by hand.

As I said before, i think you may have packed the slide with so much grease that it hydraulicly locked the slide and doesn't allow it to move. Take the grease out of the hole and put it back together....

 

[durty3]

Hey guys,
I have been so swamped at work and I have had no time to reply here, let alone look at the bike!

I have just reread the shop manual and along with Townsends comment, my procedure for the brake caliper installation was incorrect--but I still can't recall anything different in the final assembly. Possibly I am just off with my alignment, which would explain the high drag, but not the soft pedal.

My method for assembly: pads in caliper held in place by the brake pad pin, slide the front mounting bolt into the caliper bracket, then slowly lower around the rotor and line up the rear bolt and slide it through the caliper. It is really quite easy, and I don't see what this method would cause to go wrong.

I did clean the caliper and the slides, so that should be resolved, but I guess doing so again for good measure won't hurt. How much (or rather, how little) grease do you guys use? Anybody have a picture of a properly lubed caliper?

Finally, even with everything previously mentioned, I still don't think it explains the soft pedal. Even with the piece of plywood in the caliper (which was just barely thicker than the rotor), the pedal still goes to the floor. In fact, now that I think of it, the plunger appears to virtually bottom out in the master. I am more and more leaning towards an internally leaking master. Not sure what would have caused this--I just bled old fluid from the system. Any thoughts or experience with this?

Thanks!

 

[TownsendsFJR1300]

Re lube, inside the accordion boot, I put a pretty good amount in the but make sure it can move. A very thin layer on that rear pad retaining pin.

As noted earlier, the caliper has to be able to center itself when the brakes are applied. Is yours (with what peddle you have, pulling the caliper to the center
(taking up play with the piston extending?)

I only remembered the detail as like I said, I recently rebuilt the caliper. Those SS anti rattle clips are real easy to push out of place assembling in the manner you first did.

Can you borrow a Mity Vac (from an auto parts store-or buy one) and try sucking the fluid out vs pump/crack bleeder, etc?

And IS it confirmed the main large bracket with the slot has always been installed in the slot and DID NOT GET BENT(AT ANY TIME? If its bent at all, it won't allow the pads in fully and pump up (NOT likely as you can't get a pedal using a piece of wood vs the caliper).

With the caliper line bolt loosened/ off, can you get fluid to pump up/come out there?

About the last thing left is the rear master cylinder, that or a collapsed / clogged brake line hose.

There is a rebuild kit for the master cylinder, part #8:

Yamaha Motorcycle Parts 2004 FZ6 - FZ600SS REAR MASTER CYLINDER Diagram

If all is assembled correctly and still no progress, you may consider pulling the main brake line, and the line from the reseviour that fluid is making it to the master and checking that their clear. I've NEVER read here of the rear master failing, just the bent main bracket causing issues..

I would think, when you find the issue, it'll be an" oh that's it moment"...


Now Finalimpact has done reverse bleeding on the front brakes. I've never done it (and not familiar with it). Randy, can that procedure be used on the rear and if so how?
[MENTION=15974]FinalImpact[/MENTION]

 

[FinalImpact]

Is it just me or does it look like the caliper rocks sideways?
https://m.youtube.com/watch?feature=youtu.be&v=MFi8URBdFuk

When you do get back to it, simply flip the pads out of the way and verify the caliper centers over the rotor AND slides equally each direction about the width of the pads.
And when I say centers, i mean piston to the opposing pad stop.

Did you say placing a block of wood in there and bleeding gave the same pedal travel?

How exactly are you bleeding it? Does fluid come out with each stroke?

Bleeder closed.
Depress pedal.
Crack bleeder. Fluid is expelled. Lever bottoms.
Close Bleeder BEFORE allowing lever to move and return.
Repeat at least 5 - 10x.
Do this with a block of wood in place of pads/rotor...

If pedal does not firm up, start looking at the MC.
Either the port is plugged or there is blow by past the piston or if the pedal does not fully return, it will not allow fluid in to build pressure. You'll know this if no fluid comes out...

Notice caliper bracket to rotor spacing. Is yours the same?

 

[TownsendsFJR1300]

Is it just me or does it look like the caliper rocks sideways?
https://m.youtube.com/watch?feature=youtu.be&v=MFi8URBdFuk

]

Yes, it does rock/move. I just checked mine and there is absolutely NO movement of the caliper.

Something is amiss in that area....

Perhaps after doing the above (and IF NOT successful) break out the video, shoot some pic's of the caliper bracket in place, then YOU
physically assembling the pads, show the bushing installed, show the pads being installed, etc.