Bleeding one's brakes?
Discussion
I don't like vacuum bleeders because they can pull air in around the bleed nipple threads.
I use an easibleed which has a fluid reservoir which fits to the master cylinder and then connects to a spare wheel with no more than 10 or 15psi. This pressurises the system so all you have to do is go around the bleed nipples and release them and look for bubbles.
Steve
I use an easibleed which has a fluid reservoir which fits to the master cylinder and then connects to a spare wheel with no more than 10 or 15psi. This pressurises the system so all you have to do is go around the bleed nipples and release them and look for bubbles.
Steve
Having seen both types in commercial use the pressure system as described by Steve is more suited to new installations.
It is highly possible for the master cylinder to have dry areas/air bubbles during the initial bleed with the resulting lack of pedal pressure.
There are many views and theories but start at the bleeds on the master-cylinders themselves (if fitted) then continue bleeding via the shortest pipe run (nearest caliper to pedals ,O/S/F,) then work your way methodically toward the the longest line...N/S/R.
New master cylinders (the pedal end of the system) are commonly the root cause of poor pedal performance...I usually try to bleed a master first (on the bench if poss) and make sure the resevoir does not get too low as you continue the bleed. There will be air in there somewhere...the only other odd thing I have seen is the seal had become dry-stuck in the master cyl bore and when the pedal was pressed it reversed the seal, this is probably very unlikely though!
A very old method to bleed difficult or snapped bleeds was to top up the resevoir and then just crack open (1/8 turn) all the bleeds or terminal pipe joints ....leave it like this for several hours topping up as required..this nearly always resulted in a good pedal.
If you do have any pedal pressure at all get someone to press the pedal for you whilst looking into the resevoir...air in the master will be confimed by air bubbles floating toward the top of the resevoir as the pedal is pressed.
Good luck.
It is highly possible for the master cylinder to have dry areas/air bubbles during the initial bleed with the resulting lack of pedal pressure.
There are many views and theories but start at the bleeds on the master-cylinders themselves (if fitted) then continue bleeding via the shortest pipe run (nearest caliper to pedals ,O/S/F,) then work your way methodically toward the the longest line...N/S/R.
New master cylinders (the pedal end of the system) are commonly the root cause of poor pedal performance...I usually try to bleed a master first (on the bench if poss) and make sure the resevoir does not get too low as you continue the bleed. There will be air in there somewhere...the only other odd thing I have seen is the seal had become dry-stuck in the master cyl bore and when the pedal was pressed it reversed the seal, this is probably very unlikely though!
A very old method to bleed difficult or snapped bleeds was to top up the resevoir and then just crack open (1/8 turn) all the bleeds or terminal pipe joints ....leave it like this for several hours topping up as required..this nearly always resulted in a good pedal.
If you do have any pedal pressure at all get someone to press the pedal for you whilst looking into the resevoir...air in the master will be confimed by air bubbles floating toward the top of the resevoir as the pedal is pressed.
Good luck.
Edited by 738 driver on Friday 16th January 11:38
Gassing Station | Ultima | Top of Page | What's New | My Stuff