Brake advice needed

[z1000]

Fitted my wilwood six pots today and having trouble getting a solid pedal, brakes do work but just a lot of travel.

Pretty confident all the air is bled out the system and fitted new braided lines to the front and dot 5 fluid.

I was wondering if the master cylinder was up to the job as its a bit of a jump from 2 pots to 6 and just wondered if anyone else has had this problem when upgrading brakes ?

Steve

[drb5]

Yep, i know the problem mate. I was once told by Harvey Smith and AlanG to remove the bias valve.

Basically you just take the valve out the way and join up the pipes together.

I have the appropriate joiners, although not a perfect fit due to the thread not being identical, but tighten them up enough and the seal just fine.

Dunno where your based and you have have picked them up and i'd show you what to do?

[AlanG]

The removal of the bias valve wasn't to give a more solid pedal Dave, it was to allow a better pedal feel and brake progression.

 

Do the Willwoods have 2 bleed valves and are they at the top?...

 

With the engine switched off, do you have a solid pedal after you have pumped the vacuum out of the servo?

[drb5]

I had the same problem as Z1000 describes, when i fitted the Brembo's to the RA. Taking out the bias valve sorted the problem.

[z1000]

Ok engine off first pump nearly to the floor [] never moved all day, couple more pumps then better but not solid, start engine and pedal goes down but doesn't really pump up to a decent pedal.

When driving first pump well down and a couple more make an improvement but always soft.

Wilwoods have 2 bleed nipples on top.

I'm in the borders but may be at crail this weekend if i can get better brakes by then.

 

Steve

[_jac_]

Ok engine off first pump nearly to the floor [] never moved all day, couple more pumps then better but not solid, start engine and pedal goes down but doesn't really pump up to a decent pedal.

When driving first pump well down and a couple more make an improvement but always soft.

Wilwoods have 2 bleed nipples on top.

I'm in the borders but may be at crail this weekend if i can get better brakes by then.

 

Steve

 

Exactly the same prob as me. brakes are good even shit hot but have a bit

of travel, i think i will try what Dave is saying and se if that's the prob.

[AlanG]

With the engine off and vacuum removed from system, you should have a solid pedal when you press the brake.

Sounds like you still have air in the system. For all the brake fluid you should use, i would bleed all 4 brakes starting with the brake furthest from the master cylinder and working towards the brake nearest the master cylinder. i.e. passenger side rear first and finish with drivers side front.

How are you bleeding the brakes?

[z1000]

Flushed the whole system and starting at the furthest away, back bleeds pefect with a lot of pressure comingthrough but fronts are noticably weeker, is there a specific way to bleed the fronts see ing as they have 2 niples ?

[JohnSt]

I have the appropriate joiners, although not a perfect fit due to the thread not being identical, but tighten them up enough and the seal just fine.

 

DAVE !!! That is the single most dangerous bit of advice I have ever heard !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

 

 

 

[the squiggle]

I have the appropriate joiners, although not a perfect fit due to the thread not being identical, but tighten them up enough and the seal just fine.

 

DAVE !!! That is the single most dangerous bit of advice I have ever heard !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

I thought he was joking but it seems not

Ask Coulty what the handling is like on snow with the bias valve removed.  Brilliant mod for rally driving but not so good on the roads

[z1000]

Thinking about fitting an adjustable one and gonna try and bleed them again as i think there may be some air left in there.

[_jac_]

What about something like this set up.

http://cc.msnscache.com/cache.aspx?q=82417...&FORM=CVRE3

[drb5]

I have the appropriate joiners, although not a perfect fit due to the thread not being identical, but tighten them up enough and the seal just fine.

 

DAVE !!! That is the single most dangerous bit of advice I have ever heard !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

 

 

 

Well you better take them back off the RA, before Arch buys it then.

[AlanG]

Were the brakes fine before you fitted the new front calipers?

I don't know the Willwood kit, but do they have a link pipe between the two halves of the caliper? If so, it shouldn't matter which one is bled, though i would bleed the nipple nearest to the disc and then the outer nipple.

I also assume the master cylinder didn't empty out during the bleeding process and hence bring air into the system?

 

Regards bias removal, I have never had a rear wheel lock up in the time i had my car with it removed (about 4 years).  I've never had the ABS activate either from the rear with the bias valve removed and i've driven the car in all weathers. What it did improve was brake "feel" and gave better feedback on what my brakes were doing, whereas before i had a solid pedal but felt remote from the car. I would do it again if it warranted it on the car.

[z1000]

Master cyclinder was totally empty as i drained all the old fluid and replaced with dot 5, brakes worked fine before hand.

Wilwoods have a link pipe on the bottom and a nipple each side on the top.

First run i went on back end was locking up so bled it again and slight improvement but i think there may still be air in there now.

Ordered a brake stopper throught scooby net GB and will have  look and see if i can knock something up to replace the bias valve or get an adjustable one.

 

[johnnyr6]

Are the calipers sitting true and parallel to the discs? A long shot but i had probs with an ap setup ( with non ap mounting kit.) not sitting true to the disc and needing shimmed to sit right. There was a 2mm gap at the top  and a 1.5 mm gap at the bottom.

 

Don't know if this would have such an effect on the peddle but you nevr know, also, don't take this the wrong way but are you using a one way valve system when bleeding the brakes?

[AlanG]

Don't do too many things at the one time z1000.

It sounds like the air is still at the front end since the back brakes are locking up. You can compress air but not fluid, so the fronts are doing very little.

I would have kept the master cylinder topped up and just added dot 5 to the system. What would have happened (if your fluid was dirty or darker colour) is that you would have seen the fresh dot 5 fluid coming out of that particular caliper.

Anyway, onwards and upwards. Are you bleeding the brakes yourself or with an assistant?

[AlanG]

Having the AP's set up incorrectly like you mention JohnnyR6 would cause uneven wear of the brake pads. Your brakes wouldn't be at their best however until the pads had worn down to the shape of the set up

[z1000]

All sorted []

Cheers for the advice ended up being a bit of trapped air, started bleeding at the front and by the time i got to the rear offside there was still some old fluid and bubbles coming out.

Probably helped that i wasn't in a hurry to get out on the bike like last time [:$] but it was sunny.

Only problem now is there almost too good and the back feels like there doing nothing so might have to upgrade to some 2 pots after a new clutch and shocks [] but thats another thread.

Steve

 

[AlanG]

Good stuff.

FWIW i never changed the rear brakes from std despite 600bhp. Removing the rear bias valve did increase wear on the rear discs/pads, so they were doing a little more, but in 8 years of ownership i only changed the rear pads once (std pads, not uprated). Save your money unless you like bling.

[fai17]

That's good you got it sorted....I've only change my rear pads once(up-rated) and there is still life in them yet.

When will we see your car next Z1000...Knockhill or Crail?

[z1000]

Rolling road day first i think then probably knockhill if i get my suspension sorted but crail is probably a no no as i had a look and really don't want to change the clutch as the gearbox looks bloody heavy and i think a couple of hard starts would kill it.

Be assured though it will be used and abused as subaru intended at every opertunity [] (not on the road of course)