Hello all,
I've exhausted all efforts search up answers on the internet, including reading the brake bleeding discussions on this forum.
I replaced the front pads about 12 months ago with no problems. Low rear pads dash warning appeared last week, so I decided to replace them by my myself. And this decision was my critical error and where my problems began.
I'm familiar with the old fashion brake pedal pumping method too bleed the brakes on older cars. However, I am clueless when it comes to modern day ABS braking systems.
My car is a 2007 Transit Bus, it has ABS and ESP.
After thumbing around and refamiliarising with the brake caliper winding tool I had release a bit of brake fluid when I depressed the caliper cylinders.
The brake pedal is spongy, and when the vehicle is turned on to build up some vacuum pressure the pedal resistance is even worse. There is absolutely no brakes. There is some limited stopping power using the handbrake.
I've attempted to bleed the brakes using the following methods:
* old school pedal pump method
* forscan to activate the ABS valves
* presurised the system at the brake reservoir
* persurised + forscan
Old school method produced two or three drops of fluid out of the nipples.
Forscan same result.
Persurised method just pushed air out the bleeder nipples (lots of air).
Presurised+forscan = just lots of air (same result as above).
The brake fluid level in the reservoir has barely changed after 3 days of failed attempts.
I recruited my father (retired Fitter and turner and a very handy old school backyard mechanic) to help today. He cracked open the pipes at the master cylinder and barely any fluid was released. He got me to pump the brake and opened the pipes again....and still barely any fluid.
Impossible to bleed brakes with no brake fluid being supplied. What is stopping the fluid from flowing????
The brakes were in perfect working order before replacing the rear pads.
I'm using an ebay purchased ELM327 and bluetoothing it to a laptop. I'm using a current version of the forscan software.
When going through the Forscan ABS brake bleed process the rear left (step one) does not activate the ABS, but activates on the left front, right front and right back (steps 2,3 &4). On a second attempt, the rear and front left did not activate the ABS valves, front right and back right activated the ABS. On the third attempt, steps 2,3 & 4 only activated the ABS. On the forth attempt, only step 3 worked and I gave up even trying to see if step 4 was going to work.
When the Forscan activated the ABS, only a small dribble at best passed through the bleed nipples. When pressurised was applied to the brake reservoir and Forscan was used, only air passes through the bleed nipples.
After all of these failed efforts, less than 100ml has fallen in the brake fluid reservoir. The amount of air that has been passing through does not add up when barely any fluid has dropped within the reservoir. It just doesn't make any sense.
Is the ELM327 and Forscan process a waste of time.
Do you need a quality IDS to bleed the brakes on this vehicle?
Is it a master cyclinder problem, the ABS or some other modern technology issue (why is there barely any fluid moving from the reservoir)?
Or am I just missing something here?
Any assistance will be gratefully appreciated.