bleeding brake problem

[contail]

when i bolt my front calipers on tight i lose brake pressure. if you undo the bolts, the brakes are solid.if i take the calipers of completely and pump the pads together they go solid. pistons are clean and theres definatly no air in the system. basicly every thing is great until i do the bolts up. can any body help please

cheers contail

[Kylie]

Sounds like the calipers split somehow and when you bolt it tight its pulling it apart

But thats a guess...

[contail]

yeah i thought that too. forgot to mention though. there gsxr 4pots. there is a slight bit of flexing but ive got the same on the bike. to be a little more acurate. with bolts undone there normal pressure. with bolts done up, its as if ive left the bleed nipple off.
thanks for your input.:D

[shaggy696969]

Sounds like the calipers not sitting central to the disc. Check alignment,, seems like it might be biting on side quicker than other so giving a slightl spongy feel when applying the brakes.

[contail]

cheers shaggy. ive had them on and off all day. i have tried spacing them with washers etc. there pretty much sitting center. i held the leaver tight and as i did the bolts up, the leaver moved back to the bar. im just at a total loss as to why finger tight to spanner tight can make such a difference. i might try different discs tomorow.

thanks

[Kylie]

Have you looked to see if the pistons are moving excessively - get someone else to pull the lever while you look - if they're not moving you have to have a leak somewhere surely?

My lever used to come right back to the bar and the split in the caliper was so small that a couple of mechanics missed it - it was only when Grav and I took them off he noticed.

[teltwosheds]

Have you looked to see if the pistons are moving excessively - get someone else to pull the lever while you look - if they're not moving you have to have a leak somewhere surely?

My lever used to come right back to the bar and the split in the caliper was so small that a couple of mechanics missed it - it was only when Grav and I took them off he noticed.

whose a cleaver bunny:cool:.i recon shes hit the nail on the head:)

[contail]

[QUOTE=teltwosheds;513250]whose a cleaver bunny:cool:.i recon shes hit the nail on the head:)[/QUOTE

just spoke to a mate and he said the same thing so i have had a look. definatly no leaks. so far i have swapped the discs and hoses and fluid. i clamped the hoses just above the calipers and the leaver is solid. no probs there. i put some 4.5mm plates in between the pads on both calipers. brilliant, loads of pressure. bolted the calipers to the forks and nothing. 1 finger pulls the leaver to the bar. pistons arent seized either. i undone the calipers and pumped them up so they could locate them selves, then i put washers in between the caliper and forks. again worked great untill i bolted them up. its obviously a prob with the calipers. but if they dont flex and pistons move ok what else is there. oh yeah. if just use one caliper the pressure is ok. would the bike handle ok with just one caliper untill i can afford a pair of calipers.

many thank all

[odie]

What master cylinder are you using?
(Single or twin caliper master cylinder)

[minxy]

Good line of enquiry, that. This on the chop Contail?

[lowrider]

Have you looked at the fork leg mount?
If it works fine except when on the leg then look to see if the mount is fine,no hair line cracks that only move when but under pressure.

[teltwosheds]

i had a problem with a floating front caliper that turned out to be due to a crossed thread thereby missaligning the pins,,,worth checking

[contail]

nah. this is the bog standered gsxr1100L slingshot. same mastercyclinder, since my last post i tried pulling away with the bolts finger tight. front wheel lock up no probs. with them bolted in i can almost push it. also pistons move in and out with leaver. ive even over filled the cylinder and forced the calipers on and it doesnt make any difference it just doesnt make any sence.
so i think what im going to do is. remove the caliper and hose and just use it with one caliper for now while i strip and clean the other.
cheers

[contail]

well ive had enough now. ive polished the pistons cleaned inside the seels i can move them with my fingers no probs. calipers are clean and leak free. pads move ok. ive done brakes on 5 slingshots and never had a problem like this. i was meant to be selling the bike this week so i could get the hardtail sorted. oh well. if any body wants a gsxr1100L that runs great but doesnt stop then i have one for sale.:D
cheers

[lowrider]

Just a thought,i had a problem with mine binding and by fitting the wheel the "wrong way",as in against the tyre rotation arrow it sorted it.
Not sure if it would with yours,as i say,just a thought.;)

[contail]

Just a thought,i had a problem with mine binding and by fitting the wheel the "wrong way",as in against the tyre rotation arrow it sorted it.
Not sure if it would with yours,as i say,just a thought.;)

hi lowrider. there not actualy binding. i would be happy if they were as this would be a problem i could solve. im gonna see if i can borrow a caliper to see if that makes a difference but to be honest i cant find a problem any where in or on the caliper.
cheers

[Grav]

Kylie is right I reckon. She had the same bother with her front callipers and your brake problem sounds uncannily similar.

[lowrider]

hi lowrider. there not actualy binding. i would be happy if they were as this would be a problem i could solve. im gonna see if i can borrow a caliper to see if that makes a difference but to be honest i cant find a problem any where in or on the caliper.
cheers
Yeah i know just as i said,try owt when you hit something that stumps you like this.:confused:

[Kylie]

Good luck with it whatever, its a right feckin nightmare trying to tie it down, I know - i spent out on new seals, master cylinder repair kit, eventually new callipers and master cylinder and it was only when we took the calipers off the second time we found the problem.

Just one other slight thought and i can't imagine why it would do it only when bolted on - bleed nipples OK? And when you've taken the caliper apart was the rubber seals in place between the calipers? Only tiddly but could cause bother i suppose?

[contail]

lol. cheers kylie. bleed nipples are definatly fine. ive had the brake system apart cleaned checked and again again. they look brand new now:).
theres only one more thing i can change now and thats the brake pads. cant nick the ones of the hardtail cuz there honda blackbird.

i will let you all know when i sort it.

cheers all for your help.
contail:cool:

[peter-dog]

disc's aren't warped by any chance are they just a thought

[Kylie]

lol. cheers kylie. bleed nipples are definatly fine. ive had the brake system apart cleaned checked and again again. they look brand new now:).
theres only one more thing i can change now and thats the brake pads. cant nick the ones of the hardtail cuz there honda blackbird.

i will let you all know when i sort it.

cheers all for your help.
contail:cool:

Do you know what sort of pads they are? If they're the same as mine i have a few spare sets which def worked on my bike no probs and aren't completely worn - yours if they[re any good

[contail]

morning kylie. i will have a look when i get back home tonight. as far as i remember there double hh sintered road race pads. but i will double check.

thanks:)