retneprac

Well-Known Member

• Feb 15, 2018

• #1

Next mission. 2004 TD5 110
Just passed the MOT. Was surprised as I think the brakes are poor.
I bleed them twice with a pressure air kit but still spongy. pads ok, rotor's slightly lipped but not too bad.
Caliper pistons seem a little corroded but not bad. Was just pondering a general overhaul.

Rotor's, pads, fluids, easy stuff.
Complete new calipers or just new pistons and seals (how difficult are they to sort?)
ABS unit? Beyond my DIY skills.
What else makes them spongy?

Cheers all for any advice.

 

zeaphod

Well-Known Member

• Feb 15, 2018

• #2

Spongy is 99% air or moisture in the fluid somewhere - even with a pressure bleeder, they can be a pig to bleed sometimes - you may have to put a couple of litres through the system. New calipers are dead easy but can be expensive, new pistons are cheaper but getting the old ones out can be a pain. It's worth checking that the master isn't weeping inside the servo unit too.

 

retneprac

Well-Known Member

• Feb 15, 2018

• #3

Cheers. Not sure how to check inside the servo unit.

 

zeaphod

Well-Known Member

• Feb 15, 2018

• #4

You just need to unbolt the master cylinder from the servo, pull it back a little - go easy on the brake pipes. You'll soon see if the master is leaking into the servo. Much more likely the system just needs bled again.

 

Scooby22

Well-Known Member

• Feb 15, 2018

• #5

Spongy feel could be caused by flexi pipe bulging,

 

flat

Well-Known Member

• Feb 15, 2018

• #6

^^^ check all your flexi’s

Also I got the best pedal by using an air pressure bleeder AND doing the old pedal up and down technique at the same time.

I then clamped the pedal down over night and now my brakes are sharp.

 

zeaphod

Well-Known Member

• Feb 16, 2018

• #7

+1 for the above technique.