Brake calipers. Should they slide back and forth

Mr_E85Bim · Post by **Mr_E85Bim** » Mon Jun 27, 2022 6:57 pm

So I just changed my front pads and discs. But I'm a little concerned as I saw on YouTube a video where the gent explains they are floating calipers and you should be able to move them back and forth by hand.

I'm concerned as there was no way mine could be moved in this way by hand. Does this mean something is wrong?

Your thoughts and knowledge appreciated as always

AndyBeech · Post by **AndyBeech** » Mon Jun 27, 2022 7:11 pm

How much did he move it? If you've put new pads in then there's not going to be much room for any movement....If you gave the slider pins a quick clean and all looks ok and they move freely about when you put them back in then should all be fine, not much to go wrong in that department apart from damaged boots or rusty pins (both of which you would have noticed).

Rockhopper · Post by **Rockhopper** » Mon Jun 27, 2022 7:27 pm

Scotchbrite the pins, cover in red rubber grease and with no pads in the callipers should slide easily.

Mr_E85Bim · Post by **Mr_E85Bim** » Mon Jun 27, 2022 8:19 pm

In the video I watched they move back and forth by a cm or two! From what you have just said Andy, I am convinced there were no pads in when he showed that particular part.

Rock, I used some silicone grease but I'm thinking I will get some red rubber grease and add that too as the pins didn't seem to slide so freely.

Thank you both

jgerrard2003 · Post by **jgerrard2003** » Tue Jun 28, 2022 8:29 pm

+1 on the pins.

Also, the end of the cylinders are probably rusty and so might not go all the way back into the caliper. Try and remove some of it with sandpaper, but be careful not to damage the rubber dust guard.

Mr_E85Bim · Post by **Mr_E85Bim** » Tue Jun 28, 2022 8:45 pm

jgerrard2003 wrote: ↑Tue Jun 28, 2022 8:29 pm +1 on the pins.

Also, the end of the cylinders are probably rusty and so might not go all the way back into the caliper. Try and remove some of it with sandpaper, but be careful not to damage the rubber dust guard.

Ohhh I didn't realise you could use something as rough as sandpaper! I will make sure to do that when I take them apart to re-grease.

Thanks

Rockhopper · Post by **Rockhopper** » Tue Jun 28, 2022 8:52 pm

I wouldn’t do anything to the pistons - you only have one per calliper by the way. If they are so rusty that they won’t go back in then you need to be looking at new callipers. A touch of red rubber grease wouldn’t hurt though.

jgerrard2003 · Post by **jgerrard2003** » Tue Jun 28, 2022 9:02 pm

I reconditioned all of mine with new cylinders and seals, which was worth the effort as they were all ceased to one degree or another. However, I appreciate that not everyone would want to do that. I only found a small amount of corrosion on the fronts behind the dust guard. Outside the dust guard was a different story. There wasn't enough space with the new pads and the cylinders would get jammed in the caliper due to the corrosion on the end of the cylinder.

Mr_E85Bim · Post by **Mr_E85Bim** » Tue Jun 28, 2022 9:46 pm

jgerrard2003 wrote: ↑Tue Jun 28, 2022 9:02 pm I reconditioned all of mine with new cylinders and seals, which was worth the effort as they were all ceased to one degree or another. However, I appreciate that not everyone would want to do that. I only found a small amount of corrosion on the fronts behind the dust guard. Outside the dust guard was a different story. There wasn't enough space with the new pads and the cylinders would get jammed in the caliper due to the corrosion on the end of the cylinder.

How do you know the cylinder would jam? There was a lot of dirt/corrosion around mine. But I did manage to push it back in with a caliper tool

jgerrard2003 · Post by **jgerrard2003** » Wed Jun 29, 2022 11:11 am

When I installed the new pads, they were touching the disk and cylinder wouldn't go in any further. The cylinder protruded about 5-6mm and I was reluctant to force it in any further as the dust guard was in poor shape due to age. The new cylinders go all the way in so that they're flush with the caliper. That gives an extra 5-6mm of travel and they move smoothly.

I'd recommend you start with the pins as mentioned above. Make sure they're clean and have a light amount of silicon grease (although BMW state it's not necessary). If that doesn't work, then remove some of the external corrosion on the cylinders, but be careful not to damage the rubber dust guard. There might be corrosion behind the dust guard on the cylinder, but from my experience it was only light on the fronts and nothing on the rears. The internal seals were all fine.

Mr_E85Bim · Post by **Mr_E85Bim** » Wed Jun 29, 2022 11:56 am

jgerrard2003 wrote: ↑Wed Jun 29, 2022 11:11 am When I installed the new pads, they were touching the disk and cylinder wouldn't go in any further. The cylinder protruded about 5-6mm and I was reluctant to force it in any further as the dust guard was in poor shape due to age. The new cylinders go all the way in so that they're flush with the caliper. That gives an extra 5-6mm of travel and they move smoothly.

I'd recommend you start with the pins as mentioned above. Make sure they're clean and have a light amount of silicon grease (although BMW state it's not necessary). If that doesn't work, then remove some of the external corrosion on the cylinders, but be careful not to damage the rubber dust guard. There might be corrosion behind the dust guard on the cylinder, but from my experience it was only light on the fronts and nothing on the rears. The internal seals were all fine.

Thanks mate, I'll give that a try

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