Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: mattiemjbb on June 17, 2007, 05:18:32 PM

Title: brakes driving me nuts
Post by: mattiemjbb on June 17, 2007, 05:18:32 PM

so todays problem is.... i had the brake circuit open for a while whaslt i re built my back axle (about a month) ive re assembled it now and replaced all the brakes pips as they were all rusty.  ive bench bled the master cylinder as it had gone empty when it was left, ive bled it normally (at the nuts between master cylinder and abs unit, and at the wheels,  ive done it all 4 times 2 times normally with someone pressing the brake, and twice with a presure bleader, with the brake pedal been pressed too.  ive put about 2 liters through today, theres no bubbles and no leaks.

however when i step on the brake it still goes down to the floor, unless i pump it lots of times in which case it will go hard, but then after lifting off the brake the next time i press it it will sink to the floor,

whats broken now?

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Post by: daggie on June 17, 2007, 05:43:12 PM

master cylinder

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Post by: mattiemjbb on June 17, 2007, 05:51:49 PM

Quote from: "daggie"

master cylinder

what about the master cylinder?
get a new one?

are used ones any good or do i need a brand new one

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Post by: isle of man on June 17, 2007, 07:53:21 PM

master cylinder "a new one"





peter henry

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Post by: tag on June 17, 2007, 08:07:01 PM

Try lock grips on the  flexi hoses one at a time try the pedal each time if you get a brake you've found the problem .  cya.............

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Post by: isle of man on June 17, 2007, 08:31:24 PM

it's the seals that have tore and collapsed..........










peter henry

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Post by: chrisjones on June 17, 2007, 08:54:20 PM

Yup.  If you've left the master cylinder empty for any length of time there's a good chance the seals have dried out and it's shot.

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Post by: Dave69 on June 17, 2007, 09:01:00 PM

air in the system simple as that.

get a 100ml syringe and connect it to the brake bleed nipple by a piece of rubber hose. top the master cylinder up to the top. open the bleed nipple slightly and draw the fluid through using the syringe, when full close the bleed nipple and repeat until all the air has been removed or the brake pedal is like normal.

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Post by: MK1 on June 17, 2007, 09:15:31 PM

I don't know what motor you have, but I had the same problem with the CJ when she was stood with the master cylinder empty awaiting a rear brake rebuild.

She needed a new master cylinder as has already been said. It was still a dog to bleed up though, and I ended up buying a vacuum bleeder.

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Post by: greggmo on June 17, 2007, 09:34:37 PM

i would also point towards a fooked master as you have tried to bleed it with no improvement.

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Post by: tim_aka_tim on June 18, 2007, 12:02:17 AM

Had exactly the same. Paid about 100 quid for a new one from Lighthouse.

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Post by: mattiemjbb on June 18, 2007, 12:07:35 AM

Well I know its bled proper, done the old school way and with a pressure bleeder pumped around 2 litres through all together no air at all not even a little bit.  

I’ll have to order a new one tomorrow,

Only question is how come it will keep pressure for a short time the loose it again.

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Post by: mattiemjbb on June 18, 2007, 04:18:39 PM

new master cylinder orderd from lighthouse 121.03 with next day delivery compared to 272.22 from stealership. where i have to cycle down pay my money wait 2 days then cycle back again. stealership is about a hours cycle ride away.

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Post by: mattiemjbb on June 20, 2007, 12:01:18 AM

Aaaarrrggghhhh sill having brake trouble, still no feel, there is braking force will hold car in low range, bur still goes right down. I have attached a picture of a side of the abs unit is that little think that looks like a ball bearing some kind of bleeding device or alternatively is the bolt above it a bleed able nut?  Sorry to bug you all, its been a real bitch[/img](http://http://birtydastardsjeepclub.com/forum/userpix/1018_cam2_1.jpg)

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Post by: tag on June 20, 2007, 12:46:45 AM

What area of leeds you in? i live over in east leeds could have a look see,........ :)

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Post by: isle of man on June 20, 2007, 06:41:41 AM

have you fitted the new master cylinder? if so did you prime it before fitting?










peter henry

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Post by: mattiemjbb on June 20, 2007, 11:27:34 AM

i live in cookridge, reasnobly close the the airport

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Post by: mattiemjbb on June 20, 2007, 08:28:28 PM

yep all primed as per standard procedure.  I got my girlfriends dad coming round tomorrow who used to be a automotive engineer and did a lot of work on brakes!  and if we cant get the air out of the hcu I’ve had a brilliant idea... I’m going to get rid of it and go back to old school non abs, it’ll have to go anyway when I do my 8.8 swap because its  an arse to make work with abs.

So incase all does not go as hoped does anyone know what parts ill need to make it non abs.  I’m guessing the master cylinder booster and will suffice and obviously the calipers.

Does it still have a combi valve and does it have something different after, then ill order the parts from my good friends at gt4x4!