Possible to "back bleed" brakes?

[Mucci]

I mainly work on motorcycles and one of the tricks I picked up years ago was "back bleeding" the brakes. You take a syringe filled with fresh brake fluid, connect it to the caliper bleeder, crack it open and force fluid back through the system up to the master reservoir. 

 

It's WAY faster than the pump & crack method. It immediately forces all the air bubbles to the reservoir in a rush of burbling. Once air bubbles stop coming out and the fluid level starts to rise you're done. Seal it all up, pump it a few times to build pressure and you're good to go.

 

Is there any reason you can't do this on our cars? I know power bleeders exist but the syringe is so much simpler of a tool. 

['76mintgrün'02]

The 2002 calipers are a bit more complicated, with three bleeders that need to be bled in a particular order (upper, inner, outer) and I have read that it is possible to draw air in past the bleeder threads if pumping backwards.

 

Pressure bleeding is the way to go.  If you had a cap with a small tube attached (like with a Motive bleeder) you could even use a syringe to create the pressure to push it through.  It doesn't take much pressure at all.

 

I bought the Motive and it does the trick, but it is a bit bulky to store.  I just use mine as an air pump, without putting fluid in it and keep a close eye on the reservoir to make sure I refill it as needed.

 

There are a lot of threads where people share creative methods they've come up with, if you don't want to spend $50 on one.

Tom

[Son of Marty]

What Tom said, plus you would need a woping big syringe for a 4 brake system. You can make a pressure bleeder your self with parts from the big box store for about 20 bucks. 

 

PS I have a motive bleeder myself and it's well worth the bucks.

Edited May 23, 2020 by Son of Marty

[M3M3]

yes, that trick works on motorcycles, just don't bother with a 2002.

 

do not do the "pump and crack' method either.  use a pressure bleeder.  put about 12psi on it, open a bleed valve, then go pump the brake pedal half dozen times.  close bleed valve.  repeat.  simple.  effective.

[72pdx02]

9 hours ago, Mucci said:

 

Is there any reason you can't do this on our cars? I know power bleeders exist but the syringe is so much simpler of a tool. 

I wouldn’t want to force the crap back through the system.   I recently rebuilt some calipers and they had some gross sludge looking stuff inside. 

[M3M3]

[Buckeye]

Fill that bore with diluted EVAPO-RUST and let it sit for 24 hours.

https://evapo-rust.com/evapo-rust/