Brake bleeding

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Another interesting thing on the old Mondeo - changed a rear caliper so had to bleed the brakes. Used a one-man kit.
When I first pressed the brake pedal, it went right to the floor, as you would expect, but after that it only went down to normal braking travel. I opened the bleed nipple another turn to make sure, and tried again with no change. So finished up, and the brakes work fine.
Can anybody explain this? Is there some clever German device in the cylinder which releases air but stops liquid?
(it's not the first time I've noticed this, but not asked about it on a forum before)
 
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In commercials - vans and trucks - there is a brake proportioning valve on the rear axle.....this device alters the braking bias to the rear to avoid lock up of the wheels.
These days the ABS pump does this for you so a stamp on the brake pedal senses excess pedal pressure once air is expelled.
You should still be able to get fluid out with a very gentle press on the pedal.
John :)
 
In commercials - vans and trucks - there is a brake proportioning valve on the rear axle.....this device alters the braking bias to the rear to avoid lock up of the wheels.
These days the ABS pump does this for you so a stamp on the brake pedal senses excess pedal pressure once air is expelled.
You should still be able to get fluid out with a very gentle press on the pedal.
John :)
Thanks John, I'll try that if I need to, but as I said, appears to be no problem with the brakes.
 
I’m sure there won’t be any issues, the air bled out because it is compressible whereas fluid isn’t.
Any discrepancy with your brakes will show up at your next MOT test which is very accurate efficiency wise.
Personally I use two systems to bleed brakes.....first a vacuum pump at the nipple if it’s just a fluid change, or a Gunsons Eezibleed which pressurises the fluid in the master cylinder reservoir. Great if new pipes or ABS pump has been replaced.
John :)
 
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Had a change of master cylinder on an i20 last year, done by a garage. They had bother bleeding the system so left it over night to gravity bleed.
 
On several of the old wrecks I have worked on - where opening the bleed nipples is nigh on impossible - I pop the new master clinder on and allow fluid to flow through the ports. I then connect the pipes up but leave them slack overnight......often enough all is fine come the morning. Just keep an eye on the fluid level!
John :)
 
Thanks for the extra comments. Car passed MOT no problem, said the brakes are spot on.
I've had to work on the rear calipers several times over the years. The design was changed not long after mine was made, maybe the later version is better.
 
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