Caliper pistons - steel or chrome

[Wheelz]

The Bearmach rear callipers I put on my Range Rover didn’t have stainless steel pistons. They’re a reputable make so I’m surprised they are not part of this commonplace movement.

Bearmach Land Rover Defender Stainless Steel Brake Caliper Piston x 4 | eBay

[marshman]

I would guess mass car manufacturers used Chrome plate steel as it was the cheapest option and best overall compromise. Also they expect the vehicle to be in regular use, not left for 6 months of the year in a damp garage. Caliper pistons can be and are made in a range of materials, all with their individual pro's and con's. Chrome plated mild steel, stainless, aluminium, even phenolic plastic. The reason some "may" have experienced problems with sticking stainless pistons due to them expanding when hot is simple - they were the wrong size! Probably cheap knock offs made to the same size as the chrome plated steel with no allowance made for thermal expansion. Aluminium has a greater coefficient of expansion than stainless and they have been used in lighter weight racing applications without issue.

As I said I fitted stainless pistons to the 4 pot calipers on my Land Rover years ago and had no issues. Horses for courses as they say. But as with everything, if you buy cheap rubbish parts expect problems. Get properly made parts from a reputable supplier and you are less likely to suffer issues. In fact thinking back when I restored my Standard Vanguard in the early 1990's I got the front wheel cylinders refurbed by Past Parts, they bored out the cylinders and fitted stainless sleeves and a stainless piston. Reason was at the time replacement cylinders were like hens teeth and they were prone to seizing due to ...... corrosion. Nearly 30 years on as far as I know there have been no further issues with the front brakes. As Wheelz says - no hesitation to go stainless - especially on "occasional use " classic cars.

If you are really worried about thermal expansion and sticking pistons then go for titanium - pretty much ticks all the boxes - except the cost

[richardthestag]

Bearmach went broke last year, shame as they were damn good at what they did. Remaining stock and the company name have been swallowed up by Britpart - now more or less have a monopoly on Land Rover part supply. some good, some ****e. Caveat Emptor

On stainless pistons my only personal experience;

I rebuilt a complete set of Land Rover callipers, 4 pot at the front and 2 pot at the back. Sourced a rebuild kit with stainless pistons and new seals from a reputable supplier. That supplier still sells stainless pistons.

Within a month one piston on the front was leaking! I removed it, replaced the seals and rebled the system. Then within a week a second piston on the same calliper was leaking. Rather than chase my arse down the street I removed the pair and consulted with BiggRed. I sent the front callipers back to them for inspection and rebuild.

They could see nothing wrong with the install but did rebuild with their seals and electroless Nickel Plated steel pistons.

I refitted and bled the brakes, no further issues with the front brakes but a month or so later one rear calliper piston was found to be leaking.

In my opinion stainless pistons in this instance were not compatible with the AP lockheed callipers on my car. Being a safety critical item I opted not to bother testing any further.

Now I send callipers straight to https://www.biggred.co.uk/ every time, they do this day in and day out. Would appear to use electroless nickel plated steel across a lot of their products

You want to fit stainless, fill your boots - your car, your money. Me? I refer you back to post 5 in this thread.

[richardthestag]

Idle googling found this which some may find interesting

https://www.pfonline.com/articles/electroless-nickel-plated-steel-versus-stainless-steel-case-studies

[DJT]

Bearmach went broke last year, shame as they were damn good at what they did. Remaining stock and the company name have been swallowed up by Britpart - now more or less have a monopoly on Land Rover part supply. some good, some ****e. Caveat Emptor

On stainless pistons my only personal experience;

I rebuilt a complete set of Land Rover callipers, 4 pot at the front and 2 pot at the back. Sourced a rebuild kit with stainless pistons and new seals from a reputable supplier. That supplier still sells stainless pistons.

Within a month one piston on the front was leaking! I removed it, replaced the seals and rebled the system. Then within a week a second piston on the same calliper was leaking. Rather than chase my arse down the street I removed the pair and consulted with BiggRed. I sent the front callipers back to them for inspection and rebuild.

They could see nothing wrong with the install but did rebuild with their seals and electroless Nickel Plated steel pistons.

I refitted and bled the brakes, no further issues with the front brakes but a month or so later one rear calliper piston was found to be leaking.

In my opinion stainless pistons in this instance were not compatible with the AP lockheed callipers on my car. Being a safety critical item I opted not to bother testing any further.

Now I send callipers straight to https://www.biggred.co.uk/ every time, they do this day in and day out. Would appear to use electroless nickel plated steel across a lot of their products

You want to fit stainless, fill your boots - your car, your money. Me? I refer you back to post 5 in this thread.

I wondered whether Biggred would be mentioned, and I am glad they have in a positive manner. I had my Stag calipers reconditioned by them in November 2015, 24,000 miles ago, and they have been fine. No idea what pistons they fitted, but they would get my business in future.

[marshman]

Bearmach went broke last year, shame as they were damn good at what they did. Remaining stock and the company name have been swallowed up by Britpart - now more or less have a monopoly on Land Rover part supply. some good, some ****e. Caveat Emptor

On stainless pistons my only personal experience;

I rebuilt a complete set of Land Rover callipers, 4 pot at the front and 2 pot at the back. Sourced a rebuild kit with stainless pistons and new seals from a reputable supplier. That supplier still sells stainless pistons.

Within a month one piston on the front was leaking! I removed it, replaced the seals and rebled the system. Then within a week a second piston on the same calliper was leaking. Rather than chase my arse down the street I removed the pair and consulted with BiggRed. I sent the front callipers back to them for inspection and rebuild.

They could see nothing wrong with the install but did rebuild with their seals and electroless Nickel Plated steel pistons.

I refitted and bled the brakes, no further issues with the front brakes but a month or so later one rear calliper piston was found to be leaking.

In my opinion stainless pistons in this instance were not compatible with the AP lockheed callipers on my car. Being a safety critical item I opted not to bother testing any further.

Now I send callipers straight to https://www.biggred.co.uk/ every time, they do this day in and day out. Would appear to use electroless nickel plated steel across a lot of their products

You want to fit stainless, fill your boots - your car, your money. Me? I refer you back to post 5 in this thread.

Feel your pain over the leaking calipers after you rebuilt them, but just as likely to be rubbish rubber seals as "dodgy" stainless pistons. As I said I rebuilt my Landy 4 pots (AP Lockheed original) using stainless pistons many years ago now, no problems, no leaks and the pistons are still like new - and I live in a salty environment ! Pic from a storm here a couple of years ago - our house is a mile further inland, but you get the picture!

PICT0035.jpg

[mjheathcote]

I rebuilt my calipers 28 years ago with stainless pistons and silicone brake fluid, along with new master cylinder, rear brake cylinders and lines/PTFE flexible.
Never had to touch anything until a couple of years ago, new front brake pads.
Everything still A okay, with firm pedal.

[jbuckl]

Just saw ‘on the other place’ that someone was asking for advice about which caliper seal goes where.
Yikes.

[marshman]

Found the receipt for the stainless steel caliper pistons I fitted to my Landy. It was back in October 2008, so 14 1/2 years ago. As I said no problems to date! Turns out I got them on eBay from a firm called "Autopost" a Landy parts supplier in Wimbledon

[richardthestag]

Found the receipt for the stainless steel caliper pistons I fitted to my Landy. It was back in October 2008, so 14 1/2 years ago. As I said no problems to date! Turns out I got them on eBay from a firm called "Autopost" a Landy parts supplier in Wimbledon

Thank you marshman , I suspect that the more modern stuff is not made anywhere near as nicely. The pistons I used on the Range Rover were from sourced from Paddock Spares nearly 5 years ago and came in those 'orrible blue bags of despair. As you mentioned it could also have been poor quality seals, makes you wonder why someone would manufacture something so half-arsed yet safety critical.

Britpart may well have changed their supply chain but interesting to note that they are not providing the OE product in this case despite being an OEM supplier now.

https://www.lrdirect.com/606696-brake-calmper-piston-rear-rrds90

OE pistons are made by AP Driveline, I cannot find any reference that these are stainless, I am wondering why? but I expect that the electroless nickel coat or whatever they are using is cheaper and more resilient than chinesium stainless?!?

Interesting thread and nobody is being an arse either

[richardthestag]

Feel your pain over the leaking calipers after you rebuilt them, but just as likely to be rubbish rubber seals as "dodgy" stainless pistons. As I said I rebuilt my Landy 4 pots (AP Lockheed original) using stainless pistons many years ago now, no problems, no leaks and the pistons are still like new - and I live in a salty environment ! Pic from a storm here a couple of years ago - our house is a mile further inland, but you get the picture!

PICT0035.jpg

I bet you were pleased when you got back into the Landy on a day like that

[richardthestag]

Just saw ‘on the other place’ that someone was asking for advice about which caliper seal goes where.
Yikes.

I get emails asking me how to sort brake issues

There is only one way to learn though so I do try and offer advise which mainly starts with suggesting they take it to a mechanic often easier and safer than learning you messed it up the hard way

[jbuckl]

Had to investigate a rear brake repair that was done at a reputable auto centre…I saw the invoice.
the description said repair and adjustment of rear brakes.

the reality was the adjusters had been attacked with a mig welder & the drum had been attacked with an angle grinder.

the whole set had to be replaced. Backplates, the lot.

[Goldstar]

Bearmach Land Rover Defender Stainless Steel Brake Caliper Piston x 4 | eBay

As I said, my calipers didn't come with them, I didn't say that you couldn't get them

[Wheelz]

As I said, my calipers didn't come with them, I didn't say that you couldn't get them

Since you actually said you were surprised they didnt come with stainless, now you know that Bearmach along with many other manufacturers can and do use stainless.