big brake conversion....... big problems

[paul capri]

okay I dont know if i've got this is the wrong section but I thought if i put it in here then most people will see it

 

I've done the gtr 280 brake kit conversion on my capri which is 280mm front discs on monde0 calipers and rear cossy discs and calipers,

 

I've used new discs, pads, mastercylinder, copper pipes, braided flexi hoses, bias valve and I rebuilt the front callipers with new seals.

 

I've pressure bled the whole system and the pedal feels great, but when you actually brake its just scary! it pulls on one way, then the other, and locks either of the front wheels even from like 60mph! I took the front callipers off earlier to check that the pistons move freely which they do, cleaned it all up, re-bled the front and it does the same thing!

 

Any ideas?

[vibrating_Cake]

sounds like your TCA bushes are screwed!!!!

 

and you have the bias set too much to the front!

[caprinerd]

id go with tca bushes as well at the mo

[Andrade]

if you press the pedal slowly so it just touches the brakes, do you feel any vibrations in the pedal/whole car? if it's affecting steering, check for loose tie rods/steering rack. it takes a minute and if its not them you can take it out of the equation. check also you have no rubbing against the inside of the rim.

[livewire7116]

Have you checked tyre pressures?

[paul capri]

Checked tyre pressures which are fine.

 

The steering rack and track rod ends are only a few months old.

 

The track control arms are fine, they are also mounted on polybushes which are about a year old.

 

The tyres can't touch the rim even in car parks etc. I rolled the lip round and have run it on the correct width spacers so even though the wheels are 16x8s I've got plenty of clearance.

 

When you brake you dont get any steering wheel wobble, it just sends the car all over the place, however after trying to stop it a few times, a slight shake of the steering wheel does seem to develop, with and without the brakes applied.

 

the car is dangerous really, someone pulled out straight in front of me last night on a narrow road and how i kept it out of the ditch when the nearside wheel locked up I don't know.

 

Oh and the bias is only in the rear line and i've got it wound nearly all the way out at the moment, it's certainly the fronts which are causing all the problems.

[turnover]

it could be a colapsed flexi hose as it will bleed but under hard preasure you will get more to one side of the braking curcuit so basically more braking on one side,also you have got the calipers facing the correct way up,dont know wether this conversion can fit either way thats all

[paul capri]

it could be a colapsed flexi hose as it will bleed but under hard preasure you will get more to one side of the braking curcuit so basically more braking on one side,also you have got the calipers facing the correct way up,dont know wether this conversion can fit either way thats all

 

Collapsed flexi hose.... when I was sorting something out with the brakes i dropped a caliper while it was attatched to the flexi which kinked it. Didn't think anything of it. I didn't think it could cause a problem? you might be onto something there. Will swap it over and see.

[bortaf]

sounds like the fronts are doing all the work, that's how a drum braked car feels when the rears are well unajusted ?

what valving did you fit to limit the rears? the sierra valve or manualy adjustable? if sierra you may have the angle wronge possably?

What master are you using, Mk2 granny or land rover ?

 

Oops just read it's a bias adjuster, let more to the rears and see if that helps

[hellblue]

I would go to an mot station & get your bias valve set up right on the rollers (what ever the problem) but it sounds like you have way to much front & to little at the rear, the fronts are locking up either side down to the road surface also have you fed the rear calipers from the single rear feed ? the fronts may well be on before you move enough fluid to the rear ? have you got any brake dust on the rear wheels ?

[paul capri]

The bias valve is a manual type one, just has a knob that you get 8 turns on. Its a landrover master cylinder with 2 outlets, one is split right at the master cylinder itself with a T-piece to feed both the fronts.

 

There is a single hose which feeds the rears, this is where i've put the bias valve in.

 

I split the rear hose with another T-piece where the O/S flexi mounts. I then ran a separate copper pipe over the prop tunnel and used another braided hose for the N/S calliper. (rather than a copper pipe over the axle which doesn't allow you to bleed the calipers separatly).

 

Brake dust.... that reminds me. The N/S front wheel (which usually locks) has become black after a week. The O/S front wheel is nigh on clean! the rear wheels are equally dirty though.

 

Does any one else recon that if you kink a braided hose you automatically f*uck it then? I can't think of anything else?

 

Help me im looking at e30 bmws again!!

[vibrating_Cake]

got a blockage in the clean caliper by the sounds of it, blocking the pressure enough to work, but only just!

 

i.e. itll work on soft pressure because its half blocked, but on harder pressures the small blockage could block the pipeline fully causing no increase in pressure at the caliper.

 

i'd say undo, clean and re-do all the unions for the non black caliper n go from there

[paul capri]

seems logical. I'll give that a try if I get chance through the week, if not then saturday. cheers for your help guys

[herb capri]

mate i think the suggestion of flexis is bang on! as i had same symptoms and similar situation,brake upgrade,new bits ,,,,,,,,,,,wow big scare and it was one flexi!

AS YOU BRAKE good flexi lets fluid thru,car goes one way

THEN YOU PANIC press harder,fluid farts into other side and you then veer that way!!

my bet if it pulls one way first,then the other side flexi is gone

[herb capri]

all credit to turnover as i think hes got it!!!

[RS2kSX]

i had somthing simular, had load of play in the rears...