AP calipers

[robbyd]

I can't speak to AP until Monday - but in the meantime -

One of the inboard bleed screws has seized. We tried heating/cooling cycles and it eventually turned, but not the way you'd want!

Screw is out but thread in caliper has had it. As has the screw.

Can AP repair these, does anyone know?

This is on a vt2 but I'm certain it's the Monaro kit. People say it doesn't fit under the standard 18" wheels, but it's on there...

Thanks

[mfp4073]

AP do offer a full caliper refurbish service with new seals, pistons and repaint ect. A damaged bleed screw thread won’t be a problem for them.
I’m not sure of the cost but the caliper will effectively be new when finished.

[robbyd]

That's really good to hear -

maybe they re-tap with a larger diameter screw? Can't see an insert holding the pressure...

Cheers

[paddy1970]

If the damage is only in the mounting hole and the caliper body is otherwise fine, Time-Sert or Helicoil will work.

If the caliper body has cracks or structural damage, replace the caliper—it is not worth the risk.

Personally, I would strongly recommend Time-Sert over Helicoil.

[robbyd]

Will look into that - thanks.

Caliper body is good - it's just the threaded hole that no longer has threads. Difficult to tap though without damaging the angled end it closes against?

[stevieturbo]

Any decent machine shop should be able to repair, or there are places like Big Red and others who do calliper refurbs

[stevieturbo]

or some DIY-ish options

https://www.youtube.com/watch?v=4M4M8pz1tIg

[robbyd]

Thanks -

The main problem, over time, is aluminium against steel corrosion, isn't it?

[two4oneuk]

Look up North east brakes in Aberdeenshire. He is regularly machining bleed ripples out of all makes of calipers. If your not close he can do a postal.service.

[stevieturbo]

robbyd said:

Thanks -

The main problem, over time, is aluminium against steel corrosion, isn't it?

The main problem is a blatant lack of maintenance. Yes, corrosion is a well know issue on calipers, whether nipples and bolt threads where applicable, doesn't matter whether stainless or steel really, as both can have their issues although regular steel easier to drill out., hence why it should always be a basic check on a service the check the nipples and apply anti-seize.
This will ensure they are never likely to pose a problem during your ownership. And it costs almost nothing, just a few minutes of work.

Obviously if just buying a car and this has not been done.....you've no control over that. But even from brand new, this is a very sensile step to take

Sadly preventative maintenance is a rarity these days

[vxr2010]

I contacted pro calipers East Ham London for you , as I have used him before on my brembos , they said they can do it for you , they said that is based on the bleed nipples being the same as brembo bleed nippes , google implies they are the same , he refurbed a set of brembos for me , posted then to him , photos of what needed doing , quick turn around , flexibility in how to pay , some other companies would not do my bleed nipple repair , my repair being the bleed nipple thread issue same as yours

[robbyd]

stevieturbo said:

robbyd said:

Thanks -

The main problem, over time, is aluminium against steel corrosion, isn't it?

The main problem is a blatant lack of maintenance. Yes, corrosion is a well know issue on calipers, whether nipples and bolt threads where applicable, doesn't matter whether stainless or steel really, as both can have their issues although regular steel easier to drill out., hence why it should always be a basic check on a service the check the nipples and apply anti-seize.
This will ensure they are never likely to pose a problem during your ownership. And it costs almost nothing, just a few minutes of work.

Obviously if just buying a car and this has not been done.....you've no control over that. But even from brand new, this is a very sensile step to take

Sadly preventative maintenance is a rarity these days

Can't argue with that

[robbyd]

vxr2010 said:

I contacted pro calipers East Ham London for you , as I have used him before on my brembos , they said they can do it for you , they said that is based on the bleed nipples being the same as brembo bleed nippes , google implies they are the same , he refurbed a set of brembos for me , posted then to him , photos of what needed doing , quick turn around , flexibility in how to pay , some other companies would not do my bleed nipple repair , my repair being the bleed nipple thread issue same as yours

Thanks - I saw them on the internet... will phone them.

AP themselves no longer put thread repairs in. Currently waiting for a price for new caliper...

Big Redd no longer do workshop repairs but happy to sell a helicoil kit..

A few people advise against helicoil. There's a hell of a lot of pressure behind it and I wouldn't like it to fail!

[stevieturbo]

robbyd said:

There's a hell of a lot of pressure behind it and I wouldn't like it to fail!

There really isn't

Brakes, maybe 50 bar at most, and given it seals on a taper, there will be just be very very light pressure at all on the threads.

Most people tightening the bolts probably applies more pressure than there would ever be hydraulically on the threads

The only real concern is ensuring the new threads are drilled and inserted true.

[robbyd]

Well....

Super service by AP but since this isn't a 'regular' caliper, their dealers couldn't get me a price. That may change over the next few days...

In the meantime, SRS (sutton rebore) did a great helicoil with one day turnaround - so caliper back on, two new bleed screws, good pedal feel - very happy again!

Just need to find a way to stop it going sideways on roundabouts!

[mfp4073]

Glad you got it fixed. I’d be a bit nervous costing up a new AP caliper

[stevieturbo]

robbyd said:

Well....

Super service by AP but since this isn't a 'regular' caliper, their dealers couldn't get me a price. That may change over the next few days...

In the meantime, SRS (sutton rebore) did a great helicoil with one day turnaround - so caliper back on, two new bleed screws, good pedal feel - very happy again!

Just need to find a way to stop it going sideways on roundabouts!

A lighter right foot, or better tyres would be a start. Lots of bad tyres out there.