Smoothing brake discs?

[Mottie]

Motor factors are reporting significant shortages of many items at the moment, notably filters and discs/pads......things will recover in due course but I do prefer to use them rather than Ebay or whatever. So helpful they are - if there's a choice of say three filters for a vehicle, they send all three along and I return the unwanted items in a day or so.
John

Yeah, they are helpful. Also give plenty of freebies - thermal mugs, torches, calendars, pens etc. When it’s cold, they also send down a disposable mug, a cup-a-soup sachet and a roll and foil wrapped butter portion with every order. One day. I ordered a set of plugs, got my soup. Ordered an oil filter, got my soup, ordered an air filter, got my soup and when I phoned up to order some oil they said "How many bleedin' trainees have you got in today". When I told them they sent the rest of my order with enough soup and rolls for all of us plus a packet of biscuits.

 

[Burnerman]

This wretched Bipper of mine has a choice of 4 oil filters.
The motor factors have not come up with the right one but Autodoc seemed to have come to my rescue and only because I could see the filter and do a 360 deg rotation of it. Its a Purflux which I trust so we’ll see what arrives in due course!
John

 

[Nige F]

Its a Purflux which I trust so we’ll see what arrives in due course!

Purflux sake

 

[Harry Bloomfield]

There is no good reason to ever grind the disc faces, its pointless. I chip the swollen by rust edges away with a small hammer just to make it easy to get the caliper and pads in place, nothing more. A few good applications of the brake, will then bed the new pads into the disc after a mile or two. Until they are properly bedded in, you drive very carefully and leave your self plenty of braking distance.

 

[Lower]

There is no good reason to ever grind the disc faces, its pointless. I chip the swollen by rust edges away with a small hammer just to make it easy to get the caliper and pads in place, nothing more. A few good applications of the brake, will then bed the new pads into the disc after a mile or two. Until they are properly bedded in, you drive very carefully and leave your self plenty of braking distance.

Depends on if there is any significant rust on the swept face of the disc.

Sometimes the rust from the edge of the disc encroaches into the swept area. The rust abrades the pad before the pad can remove the rust and the swept area gets smaller and smaller. You often see this on the rear discs of japanese cars, particularly on the back of the disc that you can't easily see with the car on the ground. If that happens, it can be worth getting the disc skimmed.

 

[Stivino]

Depends on if there is any significant rust on the swept face of the disc.

Sometimes the rust from the edge of the disc encroaches into the swept area. The rust abrades the pad before the pad can remove the rust and the swept area gets smaller and smaller. You often see this on the rear discs of japanese cars, particularly on the back of the disc that you can't easily see with the car on the ground. If that happens, it can be worth getting the disc skimmed.

Discs are so cheap that it's not worth the time, money or the effort of getting them machined. Those days are long gone.

 

[Harry Bloomfield]

I trick I learned online and confirmed works as a fix for juddering disk brakes, supposedly due to warped disks, is as follows....

You find an empty fast road, get the car upto 70 and brake hard, but without coming to a full stop. Without a delay, get it back up to 70 and repeat, then repeat once more. Idea is to get the discs good and hot, to relieve any distorting stress in the metal.

Theory is, that disks can be warped by hard braking and coming to a stop with the pads insulating one part of the disk, which sets up stress in the metal. What ever the cause, I and several others have proven the fix works.

 

[Lower]

I trick I learned online and confirmed works as a fix for juddering disk brakes, supposedly due to warped disks, is as follows....

You find an empty fast road, get the car upto 70 and brake hard, but without coming to a full stop. Without a delay, get it back up to 70 and repeat, then repeat once more. Idea is to get the discs good and hot, to relieve any distorting stress in the metal.

Theory is, that disks can be warped by hard braking and coming to a stop with the pads insulating one part of the disk, which sets up stress in the metal. What ever the cause, I and several others have proven the fix works.

Juddering brakes are normally down to uneven pad deposits on the disc rather than actual warping. Heavy braking as you describe can help remove them, thus fixing the juddering feeling.

 

[Harry Bloomfield]

Juddering brakes are normally down to uneven pad deposits on the disc rather than actual warping. Heavy braking as you describe can help remove them, thus fixing the juddering feeling.

Possibly, you can usually see a mark on the disc, where the pad came to rest.

 

[Agile]

This discussion has covered quite a few topics now. But none as a solution to my problem!

As I am not working on vehicles every day ( or week or month ) and hopefully only a couple of times a year so I an not tooled up or experienced in getting 15 year old rusty discs off. So I need to refurbish the old discs in situ.

But I do a bit of building work and watching a friend using a cement mixing tool and a plastic mixing container that looked a much better and less hard work so I bought a mixing tool.

Now this tool looks absolutely ideal for rotating a back disc while I skim it with an angle grinder! It really is in a state. The contact area is badly scored and now only about half the active contact area ( as also described in a couple of postings above! )

Some other jobs to do first but I hope to get this one done within a few weeks!

 

[Mottie]

As I am not working on vehicles every day ( or week or month ) and hopefully only a couple of times a year so I an not tooled up or experienced in getting 15 year old rusty discs off. So I need to refurbish the old discs in situ.

What car is it? Most times it’s literally just two bolts and a screw that needs to be removed to get them off.