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Bleeding brakes (in both senses of the word)


k80rum

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Can someone point me in the right direction? I've spent the last 2 hrs trying to bleed the brakes and I'm just not making progress. Both front and rear brakes have been off the car over the last few months and I've just gotten around to refilling the system.

 

I have the AP big brakes at the front and the standard sierra calipers at the rear. I'm also using an AP race master cylinder.

 

Using new fluid, I've started at the nearside rear caliper, moved to the nearside front, offside rear and offside front.

 

The technique I used was: open the bleed nipple, have someone slowly depress the pedal, tighten the nipple and then have the pedal let up again. I also tried depressing the pedal THEN opening the nipple, closing it again and letting the pedal up.

 

Throughout the procedure I've kept the m/c topped up.

 

I've got very slight pedal resistance now, but its still possible to depress to the floor and there is JUST enough braking to hold the car against being pushed, so almost no braking power. There are no leaks from any pipes, nipples, etc. Pumping the pedal does not increase the pressure at all.

 

Could it be the brake master cylinder seals that are effectively letting fluid back in to the reservoir? I guess I'm going to need to go to AP and get some new ones to be sure.. *mad*

 

I'd welcome any other suggestions. I'm at a loss as to what to else to try next.

 

 

 

 

Darren E

 

Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 16 Aug 2007 18:15:53

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did you try pulling on the handbrake before you started to help set the pistons in the rear calipers?

 

Sounds like ther eis still air in the system somewhere, or as you say the seals are knackered.

 

I bled the whole system by myself on the csr the other night in about 20 mins, using an Easibleed.

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Hi Mav *wavey*

 

Ah there's a point.. I had the handbrake on from start to finish. As you say, that'd help set the pistons. Would leaving the handbrake on throughout adversely affect the process?

 

I'll keep checking to see if I'm getting any more air out. I've got a nasty feeling it might be the seals tho; when my assistant (SWMBO) presses the pedal, I'm getting more of a dribble out of the nipple than a high-pressure 'squirt' (all sounds a bit Carry On doesn't it? *eek* 😬) which got me to believing the system isn't building up any pressure due to knackered seals in the master cylinder *confused*

 

I think I'll invest in an Easibleed for the sake of my marriage, mine seems to have gone walkies at some point.

 

Darren E

 

Website and Emerald maps library

 

Superlight R #54

 

 

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As Mav says you've still got air in the system..don't even consider other possibilities at this time. If you're working on your own, get someone to help-it's much easier with two,if there's a problem.

 

Fronts should be dead easy, rears as you know can be a prob. If you've got flexis on the rear and you can't clear the air, consider removing them, still attached to the brake lines and jiggling them around. If not, long slow down strokes with the nipple well open 😳, tapping with a rubber mallet and I can't believe you won't see air bubbles.

PS 1. Easybleeds are for Billy No-Mates and are more trouble than they're worth 2. You won't get a high pressure squirt out of the nipple even when properly bled

Paul

 

Edited by - Paul McKenzie on 16 Aug 2007 19:10:00

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Please don't take offence, but I assume you are using either an automatic bleed tube or Bleeding off into a jar of fluid. Automatic tubes can sometimes become porous over time and can allow air back into the system

 

Alan

 

 

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Cheers Paul *thumbup*

 

I'll persevere with air removal before i resort to the seals - I really dont want to pull the system apart and i've got to admit it's more likley as it all seemed fine when it came apart 4 months ago. I was out just now and i'm pretty sure i can hear a gurgling in the pipework somewhere - I'll use your suggestions on the rears to make sure and try the easibleed approach which has always served me well in the past.

 

Darren E

 

Website and Emerald maps library

 

Superlight R #54

 

 

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Hi Alan,

 

No offence at all. I'm currently bleeding into a jar - good point about the automatic systems *thumbup* perhaps it's just as well my old Easibleed vanished. At least I can discount that.

 

I wondered if the nipples themselves could be leaking air into the system, but discounted on the grounds that I should see some seepage when the pedal was pressed if that was the case.

 

Darren E

 

Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 16 Aug 2007 19:14:22

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Hi John,

again, no offence. I've not been able to sort this myself yet, so any suggestions are VERY welcome *smile*

 

*eek* I wasn't aware my front calipers had 2 nipples...I've definitely only been bleeding one. I'll double-check to see if I can find a second but I'm pretty sure I haven't spotted it *redface*

 

Darren E

 

Website and Emerald maps library

 

Superlight R #54

 

 

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As I cant get wife or son or daughter to press the pedal 100 times I have to use easibleed and find it OK and sqirts through a whole can of fluid pretty quickly.

 

On the rear calipers I asked Stuart Faulds for any tips and he said the rear do hold air because they were designed to sit at 90 degrees to the ground not 180 if you see what I mean.

 

He recomended removing the rear calipers and bleeding at an angle and lots of tapping but I havent tried this yet.

 

The second nipple on the front ap's makes a bigger difference!

 

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A tip I was given by Freestyles Gary May was for the person pumping the pedal to also keep pulling the handbrake on and off whilst doing the rears. This seems to move any air bubbles that might be present in the calipers and certainly worked for me to firm up a recalcitrant pedal. *thumbup*

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

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I've found the VacuBleed to be very good when having to bleed the brakes solo. It draws the fluid from the caliper and as long as you don't let the reservoir run dry, it sucks the air bubbles out *eek*

 

BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery)

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