Technical Changing 4x4 Rear Pads

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Technical Changing 4x4 Rear Pads

Steve67GTV

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Hi All,
Got an 18 month old Panda 4x4. We are up to 30,000 miles and at the last service we were told that the rear pads were 80% worn (front 50%).

2 questions:

1. Is this wear pattern normal? This seems very high wear for the rear pads - and even stranger for them to wear faster than the fronts!

2. I’m fairly handy with a spanner and was thinking of changing the rear pads myself. I gather I need some sort of calliper rewind kit. Can anyone point me at the tool I need to purchase to rewind the calliper? Having read the thread on changing the rear disks I’m hoping to get away with just changing the pads this time round.

Many thanks,
Steve
 
I have previously found roughly 50/50 wear front to rear (which is unusual generally, but seems to be the norm for the 4x4 Pandas). 80/50 might suggest that the brakes have been dragging.

The remove rear pads, remove the lower bolt of the two holding the piston carrier to the back of the caliper unit. Note: if you have had the 'modification' done under warranty to keep the rear brakes quiet while reversing, you will need to remove the large counterweight too, which is, I think, separate to the bolt. The new pads likely come with a new (but short) bolt. I guess you will instead need to reuse the long one from the silencer unit?

A lever (eg a large flat screwdriver) can be used to just tease the pads away from the disc (levering the sections of the pads that are not in contact with the disc). The carrier will then swing up and round, allowing the pads to be 'pinged' out.

The wind-back tool I have is this one. The instructions will tell you how to use it. At first it seems fiddly - the loose metal plate should be held in place by the notched part of the screw as you turn the handle to wind the caliper.

You will spot that there is a peg on the back of the inner pad, and one of the notches in the piston needs to be left lined up to slide over this as you reassemble. You need to allow for the 'arc' the piston carrier swings through as it comes back over the pads (you'll see what I mean as you do this) - it is important that the peg locates in the groove.

Once both rears are done and reassembled, press the brake pedal to take up the slack in the calipers and then pull the handbrake up hard and release several times. It is this that rotates the handbrake mechanism in the calipers, and resets the auto-adjuster.

The same tool is also great to wind the front caliper piston in as well when fitting new front pads - even though they don't rotate, the tool will push the pistons straight back in.

There is a school of thought that says you should not push brake fluid back into the reservoir, but instead should open the bleed nipple and release it that way while using the wind-back tool (with a suitable non-return valve/tube and jar to collect the waste fluid). This is apparently to prevent damage to the ABS pump. Again, I am sure others here will give their views on whether this is necessary - I tend to do it because I was told I should.
 
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Always amused by the expression of wear of pads, tyres etc as % since the implication is that folk know the original pad thickness, tread depth etc. which maybe they do...

Are front and rear pads starting from the same thickness or are rears thinner having less work to do; I don't know the answers but someone here may.
 
Thanks Herts Hillhopper - that's very helpful. I'll grab one of those tools and give it a try shortly. Currently trying to get the squeal on the rear brakes sorted first.

Steve
 
Thanks Herts Hillhopper - that's very helpful. I'll grab one of those tools and give it a try shortly. Currently trying to get the squeal on the rear brakes sorted first.

Steve
If the pads are sufficiently worn, there is a springy metal tab at right angles to the friction surface that makes contact with the disc, making a squeal, which is there to alert you to the fact that the pads are worn... so maybe changing the pads will cure this :)
You can see that (the shiny metal tab) in this part listing...
https://www.shop4parts.co.uk/?name=store&op=Details&ProdID=23149&sku=273245
 
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Brought my vehicle with 28K on the clock and intermittent squeal from the rear. This turned out to be the pads not releasing and excessive wear. Main dealer did not spot this, but MOT inspector did, lucky before disc damaged. Issue was pad back is very close tolerance to aperture in caliper. Have used ceramic grease and ground further clearance on pads, which has cleared the issue. Hence minimal wear now on rear pads. Now At 53K on clock.
 
Brought my vehicle with 28K on the clock and intermittent squeal from the rear. This turned out to be the pads not releasing and excessive wear. Main dealer did not spot this, but MOT inspector did, lucky before disc damaged. Issue was pad back is very close tolerance to aperture in caliper. Have used ceramic grease and ground further clearance on pads, which has cleared the issue. Hence minimal wear now on rear pads. Now At 53K on clock.

It sounds like I should just crack on and change the rear pads - making sure they are a good fit! Thanks all for your comments.
 
Just an update, now at 64K miles, recent MOT shows still good and the grease/clearance a good fix as ~60mpg
 
Yep, already clocked it. I reckon I need to do some more grinding, to increase the clearance. That's why they are fine when cold, but start squealing when hot. Bloody physics, eh?
 
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Yep, already clocked it. I reckon I need to do some more grinding, to increase the clearance. That's why they are fine when cold, but start squealing when hot. Bloody physics, eh?
Pads were finally changed and the disc late 2020. Now up to 86K pads seized in frame, noisy but still material, so strip grind more and more ceramic grease. Looks like should add strip and grease to annual service?
 
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