Rear disc replacement

[alibongo]

I decided to save myself a few pennies and replace the rear discs and duly followed the good advice offered on this forum.
I do however have a couple of questions.

Firstly I was surprised that both caliper pistons did not need to be wound back in order to get them off, is this normal?
Secondly I am about to fit the new discs and pads, given that I have not disturbed the brake fluid is there any need to bleed the system?

[adrianclifford]

No, if you kept the pipes attached all of the time, which you should of, there's no reason to bleed. Don't forget, they will need some time to bed in so take it easy for the initial period.

Did they come off easy ?, they don't usually.

[Steve White]

The rear calliper should be free to move on the 2 bolts attaching it to the hub.
Because the whole calliper can slide, only one piston is required to move to apply equal pressure to both sides of the disc.
Its not uncommon for the calliper to seize on the bolts, resulting in only the inside pad wearing, or wearing faster then the outer, so its important to check both pads when checking for wear.

[Geoff.F]

No, you do not need the wind-back tool to get the pads off but you will need it to fit the thicker new pads.
Important Warning. Do not apply the Handbrake before you have seated the pads on the foot brake otherwise the automatic handbrake adjusment will fail.
Depending on you brake fluid level. winding back the piston may cause the reservoir to over flow. The 'Tool required is a Turkey Baster to remove any excess fluid.
Geoff F.

[alibongo]

Many thanks for the replies,

Did the Discs come of easily? - No they were an absolute 'sod'. I could have been tempted to use stronger language but in respect of public decency and to avoid the wrath of the moderators I will refrain.
Not sure if the two philips screws were original as they appeared to be made of 'monkey metal'. I had to use a centre punch to tap one round to get it out. Next door neighbours dad says I should have used an impact srewdriver that turns as you hit it .

I purchased 2 discs and 4 pads of ebay for £35 including delivery, the local independant wanted £170 to supply and fit inc VAT.
Just using the car as a runabout so got the standard solid 240mm discs, still am wondering if £35 is a bit to cheap? Will see what they look like when they turn up on wed/thur next week.

Why did I take the old discs off before ordering the new?..... Just to make sure I could.

[Laverda119]

Having a problem getting my old discs off. Calipers and holders came off no problem. The two dics retaining screws both seized solid. Had to drill those off but the discs are still on their solid. I have applied some brute force with a rubber mallet but no joy. Not sure what to do next. Any thoughts appreciated

[Reckless Rat]

Whatever you do DON'T hammer the discs to remove them or you'll end up damaging the wheel bearing as well.

[Geoff.F]

I totally agree that you must not hammeer the disc off.
I had a front disc that would not come off. A hydraulic puller would be the answer but it fitted on the end of the stubshaft but then the equal and opposite force would go through the bearing.
I have a 10 Ton press. I took the hydraulic ram, made up an extractor , then visited my local machine shop and turned an adaptor to fit over the hub to take the piston load.
No load on the bearing and the disc fell off.
Geoff.F

[Tipper]

I recall, I think, using a nut and bolt through the caliper fixing bracket in the style of a threaded jack.

[ArntyR]

I rate Tipper's suggestion; I've done it a few times.

I'd say cushion the bolt end/disc surface with a piece of hardwood if you want to re-use the disc.

In any case tighten the bolt a little, release and then turn the disc through, say, 20degrees and repeat working your disc around a circle a couple of times.

Lots of little turning pressures- don't try to do it in one - are far more effective than a large clout.

When you see a gap start to appear where the disc-retaining screws were, spray penetrating oil into the flange space and keep repeating the tightening then turning process; you're nearly there...(but mind your toes when it eventually falls off!)

Some oil/copper/grease on the flange before refit will probably avoid a repeat.

[RobboMC]

Depending on you brake fluid level. winding back the piston may cause the reservoir to over flow. The 'Tool required is a Turkey Baster to remove any excess fluid.
Geoff F.

Nothing wrong with doing it this way, but there's an alternative:

By using the tool in my picture ( a ROUNDED hose clamp, ) you can release the excess fluid from the caliper bleed point. This saves forcing fluid backwards through the master cylinder seal, which some of the Haynes manuals warn against. But get the correct tool, a normal G-clamp will damage your brake hoses. Yes this was my front end but the same tools apply.

[Charless]

If you have a little time you can flow plenty of 'plus gas' or similar freeing oil in between the old disc and the hub. The place where corrosion between these two mating surfaces has it's greatest negative effect is *happily* exactly where the excess oil will puddle. By repeating the dose and rotating the wheel the rust will all get thoroughly soaked. Once it has all been thoroughly soaked in freeing oil you can get a heat gun or blow torch on the hub return immediately before you start trying to remove the disc.
I then find I don't need to hit the disc very hard for it to come off a little at a time. I absolutely agree with not beating the disc to death (however satisfying) as the wheel bearing(s) will give up a while later. But with heat and lubrication mine have always been persuaded with minimal mallet work. The better way is described by ArntyR above.
When you reassemble the new discs, be sure to use copper loaded high melting point grease on the mating faces to minimise the corrosion problem next time.