Brake Calipers and use of Red Rubber Grease

[M80]

I have a common issue with seized calipers. I blame our climate.
Less than 2 years ago I replaced the front calipers with new due to a seized slider. They are after market to replace already after market Brembo replacements.

I added lots of Sealey red grease to the sliders and they're ok, still sliding, but I've a seized piston this time, on the new, less than 2 year old caliper.
I have freed it some and can get it sliding.
What I would like to do is extend the piston and apply the red grease behind the dust cover. On pushing the piston back there is chance of grease passing the piston rubber ring, and then coming in to contact with the brake fluid.

Is this a big no no, or as the grease instructions say 'for brake assemblies' would it be a none issue?

 

[Wighty]

My understanding is white silicone grease on the slider pins
Red rubber grease is designed to be in contact with brake fluid and piston seals and rubber . When I rebuilt both cars pistons a few years ago I coated the piston in red rubber grease to insert it past the seals .

 

[M80]

Thanks Wighty, that's the good news I like.

I'll continue to use the red on the sliders as there is a rubber seal / guider on the pin. That's in addition to the dust cap that's rubber.
I made the mistake of using the wrong grease on Goldwing brakes years ago. The brakes became tight and the dust seals wouldn't fit any longer due to them expanding.

 

[Wighty]

Thanks Wighty, that's the good news I like.

I'll continue to use the red on the sliders as there is a rubber seal / guider on the pin. That's in addition to the dust cap that's rubber.
I made the mistake of using the wrong grease on Goldwing brakes years ago. The brakes became tight and the dust seals wouldn't fit any longer due to them expanding.

No buddy , white silicone grease on the sliders , it is designed for higher temperatures.
RRG on the piston

 

[DREAMER NO2]

Never used a cirtain type of grease on any of my brake jobs and sliders pins work fine . But i do use silicone grease in the small rubber cups and on the piston dust covers .

 

[EmilysDad]

.... On pushing the piston back there is chance of grease passing the piston rubber ring, and then coming in to contact with the brake fluid.

.....

that would imply that brake fluid could/would pass the piston seal the other way .... and it doesn't

I'm the same as Dreamer .... never bought or used red rubber grease.

My R Class was the first car I've ever had with sticky calipers and I've driven 3 Vauxhalls on their original calipers to around 180 000 miles, though I sorted a caliper for Emily with a new piston & seal in her Toyota

 

[KennyN]

Only thing i have lubricated the pistons with is brake fluid on re-assembly. Some dry lube on the sliders but that is it.

In the harsh environment that vehicles operate i find that grease just attracts dust / grit turning it into lapping compound over time.

K

 

[M80]

Possibly some of my issues are due to naff German metals. Rust on sliders, more often the lower slider, has been common.
It has been related to damaged dust covers, but not always.

Naively I used to use copper grease. that would cause the rubber to swell and grab, and also no longer fit so not sealing.

Other grease, some supplied with brake components have had varying degrees of success. Trouble is many miles later when the issue might (re) occur I didn't know which grease was used (post copper grease use that is).

On this caliper the piston is tight (or was, I'll be into it again later). The dust seal sits in to a turned recces on the calliper and also into the piston turned recess.
There was evidence of some rust below the dust seal. It may be that rust in the caliper recess has pushed on the dust seal to cause a grab on the piston, some 'correct' grease in that recess may well have prevented that, if that's the cause.

 

[mioba]

Make sure you clean the slider pins on a wire wheel before regreaing and re installing.

 

[EmilysDad]

Make sure you clean the slider pins on a wire wheel before regreaing and re installing.

Hands up all those of us that have a wire wheel at home .....

 

[mioba]

Hands up all those of us that have a wire wheel at home .....

or wire brush,
or wire wheel on on a drill.

Think outside the box ED

 

[EmilysDad]

or wire brush,
or wire wheel on on a drill.

Think outside the box ED

I use emery cloth if needed

 

[noonboots]

Using abrasive wire wheels or emery cloth on the slider will make things worse. Buy a set of new pins, use the grease that is supplied. Red rubber grease is used when rebuilding cylinders and calipers. In those repair kits that is what is supplied. Copper grease is low melting point grease with copper particles in it. It should never go anywhere near a brake system. Certainly not on any rubber components and not on brake pad backings either.

 

[Wighty]

Possibly some of my issues are due to naff German metals. Rust on sliders, more often the lower slider, has been common.
It has been related to damaged dust covers, but not always.

Naively I used to use copper grease. that would cause the rubber to swell and grab, and also no longer fit so not sealing.

Other grease, some supplied with brake components have had varying degrees of success. Trouble is many miles later when the issue might (re) occur I didn't know which grease was used (post copper grease use that is).

On this caliper the piston is tight (or was, I'll be into it again later). The dust seal sits in to a turned recces on the calliper and also into the piston turned recess.
There was evidence of some rust below the dust seal. It may be that rust in the caliper recess has pushed on the dust seal to cause a grab on the piston, some 'correct' grease in that recess may well have prevented that, if that's the cause.

This was my diy journey 3 years ago , I had never done anything caliper related apart from changing pads . I did a good amount of research before I started .
New pistons are cheap , I think my thread said about £10 .

DIY Brake Caliper Overhaul Questions/Advice

When I replaced the CLK's rear discs and pads the other week , the pads on one side were a lot more worn than the other , I'm guessing the Pistons might be sticking a bit . I've not got much time in the next month to do anything , but I've been thinking about buying new pistons and seals to do...

forums.mercedesclub.org.uk

 

[EmilysDad]

...... Copper grease is low melting point grease with copper particles in it. It should never go anywhere near a brake system. ....

I put a dab of copper grease on the bits of pad where they come into contact with the caliper

 

[mattkh]

I put a dab of copper grease on the bits of pad where they come into contact with the caliper

But.....copper is a conductor.
This risks the pad ware sensor giving wrong readings.

 

[M80]

But.....copper is a conductor.
This risks the pad ware sensor giving wrong readings.

Only if you lather it into the connector. I wouldn't recommend that.

 

[EmilysDad]

But.....copper is a conductor.
This risks the pad ware sensor giving wrong readings.

If the copper slip gets anywhere near the wear sensor I'd have bigger problems than a light/message on the dash.

 

[noonboots]

The correct grease for metal contact points is silicone brake grease. Most brake manufacturers sell their own version. The Mintex one is called Ceratec. It's about £3 for a tube that should last a DIY mechanics about 30 years.