Rear Brake Issue

[alanfavell]

9er ABS

 

Rear brake issue....

 

Your ideas gentlemen...

 

The story....

 

Changing tyres I noticed that the rear pads were worn to 1mm friction material  - got some in stock so I'll just change them - No I won't ........ the rear piston refused to push back by thumb pressure (never not done so B4).  G clamp - - no, not moving.

Released the banjo on the calliper and piston pushed back with easy thumb pressure - as it should.

Tighten the banjo and pump out piston 10mm = piston moves smoothly but pedal is a bit stiff to move. Release banjo and push piston back easily, pump pedal and it moves correctly while banjo released and returns to stiff resistance when banjo tightened.... WTF?

 

Master cylinder?

Rear lines shot (originals)?

ABS fekked? (Don't think so as front OK AFAIK)

 

What ideas have you  - not including Ladyboys (9er init).    

[Trevini]

Sounds like the flexi has started to break up internally. I've had it before on cars. 

[alanfavell]

Ta Trevini. Yeah crossed my mind, but open to other suggestions - brake related

[Catteeclan]

Undo the far end of the flexi to confirm. Move back from there if you can still push back the piston.

 

Spookily, I fitted a new flexi to a ford KA last week for this reason.

[alanfavell]

Ta Catteeclan, I'll be having a look at that tin the morning :good: 

 

Priced a complete set of brake lines (F+R)  from HEL =  £377 ooohh dear.dear

[LIAW]

I had a slave cylinder get gummed up in the past that made similar problems, might be worth checking and cleaning out all components before spending on any thing, if you undo the other end as mentioned it should allow fluid to flow freely

[Snowbird]

I had a slave cylinder get gummed up in the past that made similar problems, might be worth checking and cleaning out all components before spending on any thing, if you undo the other end as mentioned it should allow fluid to flow freely

I've come across that one too on a master cylinder, only takes a tiny bit of crud in the leak back hole to reservoir to stop fluid going back.

I had it on a Z650 rear brake that got tighter and red hot, releasing the bleed nipple was the only way to move the bike, of course fluid spat straight on to the disc and burst into flames, I paniced and tried to blow flames out to no avail till some smart arse suggested it would work better if I took my helmet off....    Stangely the flames went out then.

I had to try not to touch the rear all the way home.

[alanfavell]

Cheers to everyone for your contributions -

 

UPDATE

This morning -

Released master cylinder banjo  - plenty of fluid movement  :good: & retightened same.

Released caliper banjo = some slow fluid movement with too much resistance on the pedal. Retightened banjo and applied considerable pressure to pedal and then released the pressure on the pedal  = rear wheel locked.

Tried to back flush  with large syringe from bleed nipple to released master cylinder banjo =  not happening.

 

So it looks like either  deteriorated hoses  and or an object blocking return route (as mentioned by members).

I have ordered the ABS test tool from Fowlers (I've always had great (not cheap), service from them - in today's post too), for the princely sum of £12.45 inc.postage & VAT. This tool will allow me to completely isolate the caliper hose and back flush it (and bleed the entire system if new hoses are required). It will of course be available for loan to members with ABS models once I'm done.

 

Got to get it done because I'm away camping with the bike in early November..

 

More to follow......

[alanfavell]

UPDATE #2

 

Things it's definitely not ...

Rear caliper

Master Cylinder

 

Damn Damn Damn

 

ABS Solenoid valves to check once the Zen kicks in (maybe tomorrow).

 

TTFN

[Catteeclan]

aw bugga

[bjorge]

I have a similar problem on my 2016 Ford Grand C-Max, suspecting a sticky ABS valve. Bugger!

[Catteeclan]

I have a similar problem on my 2016 Ford Grand C-Max, suspecting a sticky ABS valve. Bugger!

Not uncommon on that era of fords. I used to use ACTronics for repairs but won't deal with the public anymore. ECU testing will though.

[alanfavell]

Yep ABS pump.



Replacement new £2304.66. That price makes the bike an assembly of paperweights.



Replacement pump obtained, used & functional at a very reasonable price.



I shall replace all hoses with new, both front and rear, for my own piece of minge er peace of mind.



Original pump to be repaired n serviced by ECU Testing when I get round to it. There will be a service/exchange unit in the Carpe-TDM community eventually.



Cheers

[Trevini]

That’s a bit crap. At that price, it’d make most older bikes a pile of spares. ABS pumps seem to be an issue of a number of bikes overall, BMWs especially based on what some of my friends have said.

 

Hope you can get it sorted out fairly cheaply, although the hoses aren’t cheap, they’ll be a good upgrade.

[dapleb]

Owwwwwwwchhhhh. Will ya be bacon da road in time fur ur trip?

[poppykle]

I have seen this type of problem reported on a few forums recently. Always older bikes obviously and the main recommendation seems to be removal of the ABS if possible.  

[alanfavell]

Not going to be ready in time Dapleb... pump arrived Monday evening (yesterday), and I'm constrained by other stuff... I can take a BMW S1000XR if I want, but it wouldn't be the same as the superior TDM.

I'll be taking my time with the TDM brakes complete overhaul.

I'll post up when done.

[alanfavell]

And now I've put my back out Grrrr.