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Discussion Starter #1
Hi guys. Having trouble getting what I believe is air in the lines on my brakes. Had to sort my rear calipers out and had them re-conditioned so had them disconnected with hose clamps on the flexis. Came to refit the calipers and changed 3 of the rear flexi pipes with new braided ones, the last one was seized so left the old flexi/rubber hose attached. Bled the system with a sealey vs820 pressure bleeder and the pedal is spongy and the brakes take a while before they come in. Rebled again and got better but there still . Today I swapped the fronts over and upgraded to the 313 disc and calipers and changed the old rubber hoses to the braided ones. Tried the brakes but there still . I only used up to 15psi so hardly went mad on that front. I'm still to replace the last flexi pipe on the back. The brakes before were great. I could lock up the brakes if I wanted to.
What u reckon guys?? Carry on bleeding in the hope that it is air in the lines?!
 

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Discussion Starter #3
Well I've pumped through about 300ml of fluid at each corner so I know it's coming through. It's just there must be some trapped air somewhere. Maybe that brake regulator thing on the rear axle?!
 

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it is not uncommon for the MC to fail during a bleeding. The increased stroke in a low pressure moment allows the piston to go places it hasn't been before or at least not for a long bit, any corrosion in there can abrade seal and low pressure results.
 

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Did you say new calipers on the front? Could it be that their bleed nipples are not at the very top for some reason so air trapped above?
 

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Discussion Starter #6
Yeah new calipers all round...well reconditioned ones. The problem occurred though when I adjusted the rear ones. One interesting thing though is the bleed nipples that have been used when the calipers were reconditioned are leaking slightly. I've ordered some oe ones from vw so will swap them over tomoz and re-bleed again. I've also finally replaced the last flexi pipe to a braided item. Wish me luck!
 

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I`ve not bled t4 brakes yet, but if there is a load compensator thing, then make sure its held open whilst bleeding to allow max flow. Also worth tapping the rear calipers with a spanner, or even a 3/8 ratchet, small hammer whilst bleeding, may help free any awkward trapped air in the new calipers.
 

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no expert by any means but I have bled brakes before using an Eezibleed (good if you can get a seal on the MC) and vacuum (ok but air can get past the threads of the nipple), also the traditional two-man and one-way valve methods (can knacker your seals on the MC as noted above). found out a new method the other day though, reverse bleeding, wondered whether that might help if you've got air stuck in your calipers as, with this method, air bubbles come out in the MC. Frost sell a tool to do this, does vacuum and reverse bleeding, such tools are commonly available in the States but not over here for some reason.
 

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I used to work for Lucas Girlings in the late 80's and one trick we used to use when bleeding brakes with a pressure bleeder, was to kick the pedal down. This would shock any any trapped air out of high spots. Also worth bearing in mind the higher the pressure used when bleeding the smaller the trapped air bubbles will be and as such trickier to shift.
 

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I bleed my motorcycle brakes from the bleed nipple. I empty all the brake fluid and fill up fresh fluid with a syringe connected to the bleed valve.
 

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Did the system drain completely? Does the van have ABS?

Ive read letting air into ABS pumps and manifolds can be bad news and difficult to rectify.
 

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Discussion Starter #12
All sorted now after running it for a bit. I had to replace a brake line on the back as it was seized. Replaced that and the flexi hose so the vans now got a full braided steel hose kit on it now. Re bled it with a decent pressure bleeder and sorted. Pedals nice and hard and the front 313mm brakes have bedded in nicely. Thanks to all who have chipped in.
 

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You dont need any fancy equipement to bleed brakes. Just a lenght of plastic tubing and a small bottle and gravity feed the brakes.
 

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Discussion Starter #15
glad you sorted it. what was the decent pressure bleeder you used out of interest ?
Used a Sealey VS820. Got one for £39 delivered. Worked brilliantly. Wack a load of dot 4 in it, connect it up, pump up to 15-18psi and crack open the bleed nipple. Piece of pi$$. Used a Gunson eezibleed but it was a bit awkward. The sealey kit is so easy to use. Worth every penny.
 
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