4 pot issues

[ben_p]

hi, i bought the willwood midlight callipers fir my 172.

i have trial fitted them to Ads 172 but we have had an issue with them,


if you are driving along and hit the brakes (or let the car run and depress the pedal), the pedal hits the floor with not much braking forse, if you release and pump then there is good pedal feel and a strong bite?


the fluid is full and they have been fully bled?


anyone else have these issues?

 

[JimmyMac81]

Have you replaced the pipes with Braided Hoses and some decent brake fluid?

Thats the enxt step i'd suggest

I went from a 238mm front brake setup to a 300mm brake setup and had similar problems. new braided hoses and brake fluid solved this


Also may want to check brake slave cyclinder just in case.

 

[skinner]

Do you need a bigger master cylinder?

 

[ben_p]

have steel lines and good fluid.

 

[Hollister]

does sound like just air in the system somewhere.

I really cant think of anything else it could be

 

[Neal 182]

4 Pots can be a real Sh1t to bleed and it sounds like air still in them to me so try bleeding them again

You can try bleeding them by pumping the pedal till it's hard them open the nipple when some one still has the presser on the brakes try that a couple of times

 

[MarkCup]

How firmly mounted are the calipers?

If as you say all fluids are fresh and fully bled, it might be that the pads are getting knocked away from the disc hence you needing to pump them back into contact.

Normally only happens when taking kerb on track, but if your calipers are a new fit, maybe they're allowing that to happen some how?

 

[Big Bob]

How do you remove the air from the abs unit is it easy to do ?

 

[CHRISK172+]

How do you remove the air from the abs unit is it easy to do ?

I messed mine up when changing my fluid. Used a Gunsons Ezibleed and emtied fluid out first thinking I would be able to see the new fluid come through easier. Big mistake as when i'd finished the pedal just went straight to the floor Did it all again, after 3 calipes I tried pedal....to the floor i thought WTF .....on the last caliper I got the wife to pump the pedal whilst using the Ezibleed.....loads of air bubbles So did same on the other 3 and was spot on....got rid of all ait from system including ABS.

 

[GordonD]

If its not air still in the lines, its knockoff.

http://www.bmsc.com.au/forums/rallying-technical/507-brake-pad-knock-off.html

 

[ben_p]

the worst part of the job is undoing the bloody b*****d res!

 

[ben_p]

i was thinking of buying some residual valves too

 

[MarkM]

My shed kit still isnt 100%

Bled them about 4 times now!

They are strong under normal use (road) but stand on them from over 100mph and the pedal will hit the stop.

Could be a bigger piston area that needs a bigger master cylinder or air in the system. I have the residual valves but havent fitted them. I think these get around the problem of bigger piston area by holding pressure in the line downstream of the valves.

 

[ben_p]

are you still selling them valves to me?

where can i buy a bigger mater cylinder

 

[diamond geezer]

i had this problem with mine, tookit to gdi in the end, and they used there special high power bleed thing onit, still took 2 go's to get it right. they are just a bugger to bleed out. do your still squeel every now and then?

 

[ben_p]

yea a bit, so was it just air in the system>

 

[Andy GDI]

the largest problem is trapped air in the master cylinder.

you need to pressure bleed and slowly pump the brake pedal to fully expel any air from the system.

its a common problem, accentuated by larger calipers.

you will need two people to do this job properally, effectivly usual bleeding procedure but then pumping the pedal at the same time... (unless you have massivly oversized the pistons on the caliper messing up the fluid dispacement ratio from master cyl to caliper)

 

[ben_p]

do you use the bleed tool which hooks-up to a compressor? and pump the pedal too?

 

[edde]

where can i buy a bigger mater cylinder

You can buy them from Demon Tweeks etc.

 

[d4ve86]

what happens if u bleed the brakes with the engine running? are the pumps then active (abs pump) so u could get all the air out?

i bet im chatting rubbish!

 

[Batman]

should have just stayed with the brembo max's and carbon lorraines there insane i tell thee!