Bench Bleeding

Demon James · Post by **Demon James** » Sat Apr 01, 17 12:24 pm

APRIL FOOL

Demon James · Post by **Demon James** » Sat Apr 01, 17 12:39 pm

OK, back to work

I am replacing the brake master cylinder on the Dart and after fitting the original one last autumn and learning afterwards that correct bench bleeding should be done first

I thought I'd post a quick guide to what I'm doing this time with the new one.

I have made up two short pipes that flow back into the reservoir, the ends sit below the fill level to allow trapped air to escape but not get back into the system.

I filled the reservoir (front and rear) and then depressed the push rod until it bottomed out. This was repeated until no more bubbles appeared in either reservoir. The fluid level was topped up as required to keep the ends of the pipes submerged.

This all seems pretty obvious to me now but clearly wasn't when I first started

I'm sure there are plenty of experienced members who know this but just in case any newcomers are going to be working on a brake system I thought it might be helpful.

Hopefully I will now be able to bleed my brakes properly and get rid of the delayed sinking pedal I had last year.

I shall update on my Dart thread

Demon James · Post by **Demon James** » Sat Apr 01, 17 12:50 pm

Bubbles show air is being pushed right out of the cylinder bore/chamber

Firmer pedal here we come..............

Pete · Post by **Pete** » Sat Apr 01, 17 1:50 pm

good job, I am just about to do the same.....

Demon James · Post by **Demon James** » Sat Apr 01, 17 2:22 pm

Sounds promising, Chally coming along then?

Pete · Post by **Pete** » Sat Apr 01, 17 3:08 pm

Demon James wrote:Sounds promising, Chally coming along then?

NO, I lied; I have just been assessing the work that needs to be done and I am miles off accomplishing anything.....at least it is back in the garage from the painters.

Blue · Post by **Blue** » Sat Apr 01, 17 3:12 pm

If all you are doing is replacing the master cylinder, once you've bench bled it you can just install it and you are done, no need to bleed the brakes at all.

Demon James · Post by **Demon James** » Sat Apr 01, 17 5:31 pm

I've just finished bleeding them as I had a slight re-plumb as one pipe was too short by enough to put a strain on it so I did it anyway

All good so far, nice firm pedal that doesn't sink

I made an adaptor plate with the drawing from that link you sent, Blue

The pictures are going on my Dart build thread.

Blue · Post by **Blue** » Sat Apr 01, 17 5:49 pm

Cool, I'll be doing the same when I fit discs to the Barracuda.

MilesnMiles · Post by **MilesnMiles** » Sun Apr 02, 17 8:20 am

I did this on my truck a while back; works a treat. Just carried the newly bled m/c from shed to car and bolted it on. Job and brakes worked perfectly.
Very satisfying job and easy to do.