Does the ABS unit have a maintenance mode for changing the pads or bleeding the brakes?

Apparently some modern vehicles do have this setting, and a diagnostic machine is needed to access it.

The Haynes manual recommends loosening the bleed screws as you push the pistons back.

If the calipers are a few years old, the bleed screws are often rusted solid, and can shear off if you try to undo them.

57 minutes ago, AntonovAN12 said:

the bleed screws are often rusted solid, and can shear off if you try to undo them.

Yes, very true.

You need to give them a good spray with WD40 a day or two before you try to loosen them. Always try to 'tighten' them just a fraction of an amount before you try and loosen them, it helps to break the bond and free them.

Thanks for the reply. I don't need to do anything with my brakes at the moment.

Someone else I know that also has a Mk2 recently did their front pads and didn't undo the bleed screws.

Their brakes are working as normal so they seem to have avoided any problems so far.

The Haynes manual claims that forcing fluid back into the master cylinder can damage the master cylinder seals. I have also read that it can force dirt back into the ABS unit.

I've never opened bleed nipples to change pads.  More risk of snapping the nipple than flipping the MC seals imo.

I can't think of any Ford that needs to be plugged in for a pad change.  Later models have an electric handbrake (EPB) which needs to be put into maintenance mode when changing rear pads.  Perhaps that's causing some confusion.

It's so much easier to push the Pads back with the Bleed Screw undone and the Hose Clamped and it gets rid of the bit of Fluid near the Calliper.

Reversed Seals were a massive problem at one time especially with Vauxhall cars so I still think it is good practice to open the Nipples.

I believe more modern cars with Electronic Brake Boosters instead of Servo's do have to be plugged in for a Brake Bleed.

Clamping aged hoses is also a possible risk as it can damage them. I wouldn't try it on my car as I doubt they have ever been changed.

11 minutes ago, AntonovAN12 said:

Clamping aged hoses is also a possible risk as it can damage them. I wouldn't try it on my car as I doubt they have ever been changed.

You don't need to clamp them very hard, I've done it on 17 year old Flexible Hoses. If the Flexible Hoses are that bad that they can't be clamped then they are dangerous and should be changed.

Always makes me wince seeing TV mechanics clamp rubber hoses, again not something I'd do unless I had no choice.  Same as watching vacuum being pulled on radiator hoses.  They're always pressurised outwards under normal running, crushing them in the opposite direction feels wrong.  

Personal preference though of course.  For reference, I have snapped 4 or 5 bleed nipples over the years.  I've never flipped an MC seal.  Or damaged an ABS pump.

14 hours ago, Tizer said:

You don't need to clamp them very hard, I've done it on 17 year old Flexible Hoses. If the Flexible Hoses are that bad that they can't be clamped then they are dangerous and should be changed.

They don't look too bad from the outside. They have never been mentioned as an issue at the MOT test.

Part of the risk is that they can look fine but split when clamped.

I have clamped brand new hoses in the past when trying to bleed a system that had all wheel cylinders and hoses replaced.

I used the Laser tools orange plastic plier type clamps.

4 hours ago, TomsFocus said:

Personal preference though of course.  For reference, I have snapped 4 or 5 bleed nipples over the years.  I've never flipped an MC seal.  Or damaged an ABS pump.

Same here Tom, 

Over the years I have always done brake pads old skool by slacking the brake reservoir cap and slowing winding the piston back enough to allow the new pads to be inserted. Never flipped a MC seal or damaged a ABS pump.

Bleed nipples are hit and miss but if they can be got loose and are in good shape then I always coat the threads with a little anti seize grease or similar, I find it helps with any future issues where they needs to be removed.  

I hate clamping brake hoses but have done in the past to do calliper replacements but I always try to avoid if possible especially on older brake hoses. 

Conversely I always clamp my Hoses and have never had a Hose failure or reversed Seals or ABS problems, it proves nothing, each to their own though.

I have had the misfortune to experience Brake Fluid Boiling once in the past and it quite frightening so if a Bleed Nipple breaks then the Fluid has not been changed for years and needs changing along with the Hoses that can't take being clamped in my opinion.

I always loosen the bleed nipples when changing pads as it is the lack of exercising them that causes them to seize and so any opportunity outside of fluid renewal to do so is worth taking in my view.