Brake discs rusty on the inside

[Les Millington]

Having repaired the rears I've now turned my attention to the front brakes in a bid to improve performance. The car pulls up without deviation, just not very well. Looking at both discs from the wheel side they seem fairly normal, shiny, used. Peering through the inspection holes on the backplates all I can see is rust covering both disc surfaces, not used. All the brake components were replaced by the PO about 5,000 miles/4 years ago. The pads look reasonably thick and are all a little bit loose in the carriers. Can anyone point me in the direction of why both discs should have the same problem and how to rectify please.

[stillp]

Inside pistons seized in the calipers?

Pete

[Les Millington]

That's what I'm thinking but is there any reason why both should be the same?

 

[stillp]

Well, is there any reason why they shouldn't be the same? Maybe the shrouding by the backplate has something to do with it - perhaps the inner pistons get hotter, or stay wet longer er after they get splashed, or something else.

Sounds like time for new pistons and seals, whatever the cause.

Pete

[Les Millington]

You're absolutely right, no reason at all, just my suspicious nature I suppose. I'll go down that direction, would stainless pistons be more reliable?

[SuzanneH]

Hi Les,

SS pistons are much better but you must ensure that the system is thoroughly bled to remove any water even if it is DOT5

 

Roger (not Sue)

[Les Millington]

Thanks Sue, didn't know about the water but certainly intended to bleed anyway having done the rears. I'm using DOT4, is that ok?

[stuart]

Its possible the PO split the calipers and didnt use the right seals between and so only one piston is working.

Stuart.

[stillp]

16 hours ago, stuart said:

Its possible the PO split the calipers and didnt use the right seals between and so only one piston is working.

Stuart.

Wouldn't that be more likely to stop the outer piston working Stuart?

Pete

[Les Millington]

Thanks Stuart and Pete. Looking at some other posts the seals and pistons seem to be a bit of a pain to replace so I'm thinking maybe complete calipers might be best for my capabilities.

[stillp]

Getting the old pistons out might be a problem - replacement calipers would certainly be easier, and would also deal with the possibility that Stuart suggested.

Pete

[John Morrison]

Hate to add to your costs Les,

but if the calipers have only been pushing on one side,

then thta's how discs break around the hub, seen it happen and its not funny, at least have a real good look,

if not change if it has run like that for any length of time?

John.

[stuart]

10 minutes ago, John Morrison said:

then thta's how discs break around the hub, seen it happen and its not funny, at least have a real good look,

 

John.

Happened to me back in the 70`s on a MK2 Jag, very frightening with all the noise and the sudden dive towards the centre of the road when I instinctively braked (It was a N/side front!)

Stuart.