DIY Brake Caliper Overhaul Questions/Advice

[Wighty]

I assume Mrs Wighty was at work or out shopping or otherwise engaged elsewhere ....

She was operating the footpump . Approval was sought first !

 

[Blobcat]

She was operating the footpump . Approval was sought first !

Did't go the Christian method* then?

*Ask for forgiveness

 

[Wighty]

Did't go the Christian method* then?

*Ask for forgiveness

Its her car i'm repairing so ive got more leeway and understanding than if it were mine

 

[Blobcat]

Its her car i'm repairing so ive got more leeway and understanding than if it were mine

Getting ahead on points then, wise move

 

[Wighty]

Got the calipers back on the car , with new Brembo discs and pads on the front . I bled the small amount of air from the front calipers after refitting them . Both calipers have new bleed valves in , but one of them appears to have a very slight weep from the bleed valve thread , i tried putting the old one back in with the same leak .
Im wondering if the seat is a bit corroded or uneven . I may try tightening further tomorrow ? My neighbour wondered if using a tint amount of cutting compound on the end of the bleed valve may work ?
I take it any form of tape/sealing compound is a no no ?

 

[Flyinspanner]

Looks great, the weeping - are the shoulders of the new bleed nipple the same as original, check it’s not ‘longer’ threaded bit as it may bottom out without the shoulder sealing?
Could thread seal be used?

 

[Wighty]

Overhauled the rear calipers today , each caliper had a piston either side . Brake parts advised me not to split the calipers .
Took 5 hours for the first caliper . Had loads of trouble getting the pistons out , initially with a footpump (which worked a treat on the fronts ) , then various pliers all with no luck .
Eventually i reconnected the caliper to the car , put some wood in the gap and pressed the brake pedal until they were 3/4 of the way out . That saved the day .
Second caliper i pushed the brake pedal the moment i had the pads out until the pistons hit the disc . This second caliper then took 1.5 hours with my new found knowledge .
I didn't paint these rears , i'll do this another time , i wanted to get them both done in a day .

 

[Wighty]

Looks great, the weeping - are the shoulders of the new bleed nipple the same as original, check it’s not ‘longer’ threaded bit as it may bottom out without the shoulder sealing?
Could thread seal be used?

At the moment they are all dry , ive ordered some new ones up . When i did the rear bleed valves , i made a point of cleaning all the threads , then greasing the new valve and working it backwards and forwards repeatedly , maybe this helps them "bed in" against the base of the valve ?
When the new front valves arrive i'll make a point of trying this procedure first .

 

[Oldspanners]

At the moment they are all dry , ive ordered some new ones up . When i did the rear bleed valves , i made a point of cleaning all the threads , then greasing the new valve and working it backwards and forwards repeatedly , maybe this helps them "bed in" against the base of the valve ?
When the new front valves arrive i'll make a point of trying this procedure first .

Really great job!
I'll know who to send mine to when the time comes.
What's your hourly rate

 

[John Laidlaw]

Patient man...

 

[Wighty]

Really great job!
I'll know who to send mine to when the time comes.
What's your hourly rate

My hourly rate is extremely low , but the number if hours it takes makes me really wealthy

 

[Wighty]

Patient man...

Only at DIY tasks , anything else not so much

 

[Wighty]

Worked some new bleed valves into the fronts , in and out with red rubber grease about 10-20 times each in order the clean all the threads out . Hopefully this will help them seat properly .

 

[Wighty]

That seems to have sorted the bleed valves . I was a bit shocked at the rust inside the bleed valve threads . Apparently bleed valve threads are designed to allow air past them , this of course allows water in .
The advice i have followed to grease the threads will hopefully prevent further deterioration .

 

[EmilysDad]

That seems to have sorted the bleed valves . I was a bit shocked at the rust inside the bleed valve threads . Apparently bleed valve threads are designed to allow air past them , this of course allows water in .
The advice i have followed to grease the threads will hopefully prevent further deterioration .

The air/brake fluid passes through the centre of the nipple, not passed the thread.

There's a cut-away diagram down the page .... https://drriders.com/brake-fluid-weeping-out-of-threads-on-bleed-nipple-t14468.html

 

[Wighty]

The air/brake fluid passes through the centre of the nipple, not passed the thread.

There's a cut-away diagram down the page .... https://drriders.com/brake-fluid-weeping-out-of-threads-on-bleed-nipple-t14468.html

It does , and a clean job it was when the bleed pipe it was . I had read somewhere the other day about the looseness of the threads . The fact that rust was in the threads down to the seat , shows that the grease idea might prevent this in the future ?

 

[EmilysDad]

.... shows that the grease idea might prevent this in the future ?

It will.
Bleed nipples do have a tendency to shear if they're tight because the hole down the centre makes them that bit more fragile.

 

[Wighty]

It will.
Bleed nipples do have a tendency to shear if they're tight because the hole down the centre makes them that bit more fragile.

Cheers buddy , ive got 4 new ones now and didnt use a breaker bar to put them in , so fingers crossed .

 

[Conor]

A great thread and well done!

I will be sure to re-visit this thread when I do mine. I'm a bit worried about using the car to remove pistons given the SL has SBC.

The "backstreet mechanic" video is very good, and he is Irish too

 

[gassed up]

Finally got the courage up to do the brake refurb myself . Did a bit of youtube research and found a really good description of the job by a guy called "back street mechanic " . He explained what to do well and advised using a footpump with a car tyre valve screwed into the brake caliper as a means of pressurising the piston out .
View attachment 51743
This is the piston pushed out to the point it can be removed . The dining room table provided a comfortable work bench .
After getting the piston out and another thorough clean inside , i fitted new inside seal and outer rubber seal with the red rubber grease provided . I could have probably reused the piston but for £10 i fitted a new one .
With care and the right tools , getting the new piston in was fairly straightforward .
View attachment 51745
After using wonder wheels cleaner , degreasant , brake cleaner , power drill with wire attachment , angle grinder with wire attachment , wire brushes and screwdrivers as scrapers . A coat of spray paint just to freshen things up and they look like new . Im well pleased .
The parts came from www.brakeparts.co.uk (other companies , but not that many are available )

View attachment 51746

If I did that on my dining room table and my darling wife caught me then it would be the last time I sat at it.