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Rear brake pedal travel

dazthephot

dazthephot

Joined Apr 2012
207 Posts | 0+
So following on from my efforts to sort the rear brake out. How much travel in average have you guys got on the pedal?
I have about 3 inches before I get solid pressure. Which makes it awkward to brake effectively.
 
Assuming your system's bled thoroughly just undo the lock nut on the lever (pointing towards the cylinder) & adjust accordingly.


HTH
 
do not use the cylinder adjustment to change the pedal travel or you will get it wrong then burn out the disc & pads a short distance down the road..

the very end of the pedal where the rubber bit is can be adjusted, it is more than enough adjustment to change the pedal position to how you would like it to be.

if its genuinely a massive amount of freeplay before the rod starts pushing the cylinder, feel free to adjust that, just leave a few mm of freeplay!!
 
Not being funny fella but why is there an adjuster there if it shouldn't be used? Common sense dictates the lever point shouldn't be touching the cylinder piston, but close to it.

The OP stated he has 3 inches of travel, the elliptical lever knob won't take up any slack, it'll just make the first contact with his boot higher or lower, ergo the only adjustment left is where I've stated.
 
after watching that i wouldnt be surprised if you havent got some evil little bubbles hiding out in the master

and the reason i was shouting about not using it was because some of us fail in the common sense department and dont leave enough freeplay on the pushrod resulting in very dangerous lockups, so trying the "foolproof" adjustments first is best ;)
 
I bled through about 300ml of fluid and I did bleed it properly with the calliper off and elevated.
The pressure, as it is, is holding. I wondered if it was worth doing it again but winding the push rod back out towards the pedal first. That way there's more space for fluid in the MC which should mean more pressure available right?
 
The cylinder piston can only come back so far, which it undoubtedly is already doing. Have you by any chance changed the brake lever? From memory later model ones are shorter (or is it the other way round?).

If you pump the pedal & the bite point gets higher you'll have air in the system still.

HTH
 
I haven't changed the brake lever.
Do you think the MC needs changing? I have bled it repeatedly as per the workshop manual and have expelled all air bubbles within about 300ml of fluid. The last time I did it (1week ago) 3 or 4 pops of big bubbles came out. I'd never seen that before, just tiny bubbles. Also when I looked in the milk bottle I used to catch the old fluid there seemed to be tiny black fragments in it. This made me wonder about the MC seals but I can't be sure the milk bottle wasn't dirty before I started.
 
If the seals are gone you wouldn't get any solid pressure. By solid I mean when the lever is fully down it doesn't go down any further after time. Assuming you do have that, and the biting point doesn't get higher if you pump the brake lever indicating air in the system, it has to be mechanical. Looking at the vid I'd say you have a fair few turns left on the adjuster.

Maybe go back to basics. Did the lever always have that length of travel? If not has it gradually got worse or did you change things around & suddenly it was that level? If so what did you change/fiddle with?
 
PaulW said:
If the seals are gone you wouldn't get any solid pressure. By solid I mean when the lever is fully down it doesn't go down any further after time. Assuming you do have that, and the biting point doesn't get higher if you pump the brake lever indicating air in the system, it has to be mechanical. Looking at the vid I'd say you have a fair few turns left on the adjuster.

Maybe go back to basics. Did the lever always have that length of travel? If not has it gradually got worse or did you change things around & suddenly it was that level? If so what did you change/fiddle with?
Click to expand...

I would agree with Paul, i also think there is some adjustment left in the rod it does not take much to make a difference as i said in your initial post
 
Ok, well the rear brake has always been poor so I've kinda ignored it and just used the front. Not ideal I know.
After bleeding it properly, it's the longest this level of pressure has lasted. Now I've got it I want to try and better it to get a really good back brake as per other people's.
Is the pedal splined? Meaning if the pedal comes off on its own and rotates clockwise slightly to bring it closer to my boot that might help as long as I don't rotate it too much so as to ride the brake continuously.
 
The biting point does get higher when I pump the pedal. So does that mean there is still air in the system?
It only takes two or three pumps to bring it up.
 
Quick reply as I'm halfway through ripping another Mille apart. Pedal's not splined. You've still got air in the system. They take for ever to bleed through, probably 3-4 flushes. Then it'll stop working again a week after. If you really want a working system you'll have to mount the cylinder away from the engine, AP rearsets do the job. Search on here or aprilia.me for the definitive how to guides for the standard system, ignore your Haynes manual.

Dunno why I know so much about this, my back brakes are simply ornaments :biggrin
 
Ha ha thanks for the tip. I guess I'm trying to avoid the spend and probably reinvent the Aprilia wheel!! If only they'd listen to us!
 
sorry but there are plenty of us out here with fully working aprilia fitted rear brakes.. its all about patience and using the right technique

i would suggest you undo the MC mounting bolts so you can angle it with the bleed nipple at the highest point then see if you can coax any bubbles out

if memory serves.. i had this exact problem, got annoyed and pulled every single thing to bits, calliper to pieces, MC apart checking all the seals etc, everything was fine.. bolted it back.. spent hours bleeding it and boom it worked :D not sure if you went through all that suffering it would definately fix yours but like i said... patience ;)
 
Thanks. I will persevere, after all it's just a simple hydraulic circuit.... He says with a raised eyebrow!
Cheers for the advice.
 
When you've had enough of ******* around with it, relocate the m/c vertically on some rearsets, and you'll get yourself a perfect pedal....first time.
 
I had three years of trying to sort it.
two aprilia dealers (one was southern cross in kilburn...one of the most experienced dealerships in the country)
a few other dealers.
numerous 'experts'.
all could get a solid brake
but just like when I did it
it lasted a few hundred miles & it was gone again.

don't let anyone tell you you're doing it 'wrong'
chances are they have not come across an awkward one.

I bit the bullet & bought some rearsets a few years back
I bled it (once) and I've not needed to touch it since.
 
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