Trouble bleeding brakes?........you won't believe this!

[DL]

Hi gents,

We're talking about a 74/81 2 door hybrid, Chev, C9, but the most important thing is that I'm using the '81 Lockheed braking system. Had probs in the past bleeding the brakes when it was first put together.

Got a stack of stuff from Paddocks including stainless braided +2" brake lines, new master cylinder and all new pistons and seals for the calipers and slotted rotors from DBA.

Put it all together and ...... it won't bleed properly. Can tell something is REALLY not right.

With this system both the primary and secondary circuits are both in operation normally.

Primary circuit is the part of the MC closest to the booster. Powers the top (front) pair of front pistons.

Secondary circuit powers the proportional valve and the rear calipers and the lower (rearmost) pistons at the front.

I have the relevant workshop manual which clearly shows the plumbing arrangements as they are supposed to be and mine has been plumbed from the MC to the front brake hose mounts the wrong way round.

Primary supply was going to the secondary front pistons and vica versa.

I believe this would have been done in Sydney in 81.

Easiest way to correct this was to swap the front hoses to the 'wrong' supply lines on the top brackets on the inner fender.

Brakes instantly bleed like they should. Stops like a normal car.

Revelation.

Have looked at all the photos, all the diagrams etc and the fault is definitely in the hard plumbing from the MC to the front hoses.

If you want to check yours - work backwards.

Primary circuit front caliper pistons are top front both sides. Supplied by the top pipes at the rear of the caliper ( joining the bottom connection at the lower brake hose mount then (should be) connected to the rearmost line on the fender bracket). These should connect DIRECTLY with the pipes connected with the part of the MC closest to the booster.

I did have my front brakelines arranged as per factory all models, so the problem was more 'interesting'. All photos and diagrams confirm that mine has been hard plumbed wrongly at the front in the engine bay.

cheers, DL