Rear brake ineffective

[steadythebuffs]

While I'm waiting for a replacement front brake rig, I've decided to tackle the horrible back brake, and would appreciate your thoughts, chaps.

The brake works, in that it engages and disengages easily enough, stopping the wheel (bike on centre-stand), so that it's impossible to turn by hand.

In road use, two problems arise:
1) the brake offers very very little stopping power, at any speed. You can feel it dragging a wee bit if left on (see 2), but it's basically useless.
2) the pedal gets stuck - you have to slip a foot under it and lift to disengage, which it does fine. There is little travel in the pedal.

I've cleaned and WD40'd the pedal linkage, and tried freeing it up. It's still a bit flakey/rusty. As soon as I can get hold of some circlip pliers, I'll dismantle all the elements of the linkage, clean and grease.

Assuming that doesn't work, is it possible that the return spring is not doing its job - it seems oddly placed BTW, running parallel to the brake lever, when you'd think it would be more use towards 90 deg. It is barely disturbed by the pedal movement.

Or is the spring inside the pushrod mechanism supposed to carry the bulk of the 'return' work?

Could the pedal heght be adjusted too much in one direction so the external return spring doesn't get enough stretching? It looks to be at normal height.

The bike hasn't had a lot of use lately, as you know - is it just a case of pumping pedal for an hour??

pads look ok, fluid level and colour ok

Any thoughts?
Buffs

[lieven1]

;D
if you didn't opened the brake lines ,so no air inside?
I would think the seals in the brake pump are worn.
can you push the brake padle all the way down?
Or do you get pressure build up?
if you do get pressure it's probably just rust in the pivot shaft for the pedal.

(srry for the spelling (from belgium)

hope i helped you a little

[steadythebuffs]

thanks for the reply, lieven

the brake works normally - increased pressure the more you push the pedal - so I don't think it's a fluid problem. There's so much pressure that it's almost the opposite of air in the system!
....but no great stopping power.

[McF]

Hi
it sounds as though you need to strip the brake pedal down and clean it all up, then give it a good greasing on reassembly. The pedal should move up and down freely. The return spring should be mounted from a lug near the top of the alloy "hanger" that the pedals etc are fitted to and connect to the forward of two holes on top of the brake lever. Fitted correctly it will be at right angles to the pedal and be extended when you press your foot down. The rear of the two holes is for the brake light switch and has another, smaller spring fitted.

I can take some photos of my spare bike's parts if you want to see how it looks and post them here.

[dpmiller]

If the pedal is hard but stopping power is poor I'd be looking at a seized caliper or slides.

[steadythebuffs]

a photo would be great McF - thanks
Your description doesn't tally with how mine looks.
If you've got a Haynes manual, mine looks like the picture on page 7.14 (9.24) - but I wonder if they've unclipped the spring!
BTW, my plastic sleeve is at the other end of the spring (nearer the front of the bike), wonder if that matters.
Then again, the Haynes picture all looks suspiciously clean - not like a real bike at all.

A good regrease is the first step. I'd be surprised if the piston or slides were seized, but that'll be step 2 I guess.
thanks for the replies

[Jake]

Noticed the same problem with rear brake when I bought my bike…(ie very little grip). It improved when I had braided hose and EBC HH pads fitted.

The Hawk manual might help:

www.hawkworks.net/manual/14.html#14-17-brake-pedal


Jake.

[McF]

I'll see what I can do for a photo tonight
It's a lot easier when bike #2 is in bits already!

and I can only echo Jake's comment re braided hoses, I got a set front and rear for £60 with all stainless fittings. Popped them in and no more swelling hoses and sponginess, they've got a nice "bite".
It's more like "stopping" power than "slowing down" power now, but still not up to the Anchors I used to enjoy on a CBR 600

[steadythebuffs]

hold fire on the pics thanks Mc - job done (sort of), and the spring is clearly in the right slot.

I managed to take the brake pedal off - clevis pin took some persuading, but not half as much as waggling the pedal itself. Soaked in WD40 and it still took half an hour's frantic wrist action to get off (and they said no good would come of it... )

well it was bone dry, and rusty. Even disengaged from the clevis pin I could only move it about 10 degrees, which explains the lack of return.
So everything in a bucket of muc-off and water, add toothbrush. Bung on a load of grease, clober it all back together and sweet lord it's worked. The pedal now twangs back with a very satisfying action, smooth as silk.
I did a little dance.
I'm still throwing the odd shape two hours later.

No road test yet - still waiting on the front brake rig which was only despatched today (bought Friday, so what happened to Saturday, lazy bugger)
but it's all gravy this end, engaging and disengaging ok, brake light coming on.

yipee
Buffs

BTW, if you're going the same route - ie you've removed the pedal hanger to get at the brake workings - my experience was that you need to replace and torque the front two bolts first, ignoring the one that holds on the end can.

Do it the other way round and the can bolt seems to drag the others slightly out of position, making stripping the threads a bit more likely, if you try and force them in. They seat in softish metal, but the can bolt ends in a (replaceable) nut (at least mne does)

[McF]

Ha ha and I see you're online too. I've just got in and having a brew, thought I'd check out your Haynes ref.

Pleased you think you have it, sounds a proper headache.

I've just noticed coolant running from the front rocker cover so it looks like my thermostat housing repair was only good for 50 miles. I hope the replacement item hurries up!

I'll drag the hanger, pedal and springs down from the garage loft just in case you still need the photos.

The Haynes manual looks familiar, and the springs are visible, they have me wondering what angle they lie at now!

Have I confused memories of my BMW R80 brake lever with Aunty's? Looks as though it's spanner time!

I'm embarassed!
the two springs lie almost horizontal when it's all fitted to the bike and do therefore appear to be in line with the brake pedal. I checked the Riva site for a quick Fiche 216.37.204.203/Honda_OEM/HondaMC.asp?Type=12&A=80 select 1988 and then the 650 Hawk. The hanger plate is clearly different but I thought the rest would be the same.

My new motto: When in doubt - look!

I've checked the beemer and that's the one I was thinking of

Offers of photos are still open, if you can trust them!

[steadythebuffs]

cor, wish I had a garage loft. or a garage (where's the envy smiley?)

BTW I'm 'signed in forever', which I guess makes it look like I'm online when I'm not.
I've actually been standing outside by the bike waiting for people to walk by my house so I could bring up the subject of the DIY triumph.

it's dark now so I've had to come in.