DB9 brake piston seals

[Markchip]

Hi guys,

Just about to pick my 2005 DB9 up from my independent specialist after a service and there's one issue they haven't been able to solve immediately. My left rear caliper is leaking slightly from one of the inner piston seals but apparently replacement piston seals (not the dust seals) are simply not available - anywhere! Unless you get very lucky.

The risk of ignoring it, especially over time, is the pads and discs will gradually get contaminated leading to poor performance and wear plus a chronic squeal. Has anyone else faced this problem and how did you solve it? The only solution I've been given is to buy a used caliper in, hopefully, good condition.

Cheers, Mark

[ds2000]

You could try a couple of brake specialists, I've used bigred in the past but not for the Aston, they may be able to help you out.

You really don't want brake fluid leaking anywhere, if it gets on your wheel it'll pull the paint off, its horrible stuff.

[KnowsAnAston]

If it's leaking fluid, chances are that it's also drawing air into the system too, as the DB9 has cross split brake circuit, this might eventually start affecting the braking on the opposite front caliper.

Not sure if you can source them, might need a specialist Brembo supplier to order, but the seals and dust seals for a DB9 rear caliper are:

Dust Boots:
- 20.4872.44
- 20.4872.43

Piston Seals:
- 05.7691.44 (36mm)
- 05.7691.43 (34mm)

[Markchip]

Thanks for that. It should be a great bit of help if I get the all-too-familiar "Sorry, we can't source the part" excuse!

[v8maniac]

KnowsAnAston said:

Not sure if you can source them, might need a specialist Brembo supplier to order, but the seals and dust seals for a DB9 rear caliper are...

Do you have part numbers for front calipers (44/40mm) as well? Thanks in advance.

[8Tech]

v8maniac said:

KnowsAnAston said:

Not sure if you can source them, might need a specialist Brembo supplier to order, but the seals and dust seals for a DB9 rear caliper are...

Do you have part numbers for front calipers (44/40mm) as well? Thanks in advance.

I keep 40/44 seal kits in stock. Email me on [e-mail] for details.

[8Tech]

Markchip said:

Thanks for that. It should be a great bit of help if I get the all-too-familiar "Sorry, we can't source the part" excuse!

I supply Brembo seal kits, email me (see above details) They are readily available.

Edited by 8Tech on Thursday 28th April 19:58

[agaton12]

What are the chances it is leaking because the piston is corroded?

[Markchip]

The piston is an unknown quantity at this stage as I haven't yet taken it off, let alone taken it apart. My hope is obviously that it's OK otherwise it will be yet one more part to source! Is it possible to deal with a small amount of corrosion with an emery cloth or will there inevitably be small pits which will continue to allow it to leak?

Cheers, Mark

[KnowsAnAston]

If the pistons are damaged, you can try these Brembo numbers:
- 20.7967.15 (36mm) - 20.7967.14 (34mm)

Front part numbers should be as below.
Dust Shields:
- 20.4872.48 (44mm) - 20.4872.46 (40mm)
Seals:
- 05.7691.48 (44mm) - 05.7691.46 (40mm)
Pistons:
- 20.7967.19 (44mm) - 20.7967.14 (40mm)

Hope that helps!

[8Tech]

Markchip said:

The piston is an unknown quantity at this stage as I haven't yet taken it off, let alone taken it apart. My hope is obviously that it's OK otherwise it will be yet one more part to source! Is it possible to deal with a small amount of corrosion with an emery cloth or will there inevitably be small pits which will continue to allow it to leak?

Cheers, Mark

You may find that the piston has corroded slightly because Brembo use aluminium pistons in an aluminium body and the "dust" seal fitting is very poor. When this then detaches, water gets between the piston and calipers and they corrode. I have steel pistons available for the 40/44 applications but only alloy pistons for the 34/36.

Cleaning both with fine abrasive often works fine if the corrosion is just on the surface but the problem is always getting a new dust cover to reinstall on the caliper where it is corroded.

[BamfordMike]

At the risk of advising something deemed lavish and over the top, why not just buy a new calliper?? or if you really must, a second hand part. Chap, this is your brakes! What happens if you pile on the anchors at 80mph on motorway if needed to make an ABS stop? At the relative peanuts price of a shiny brand new calliper in a box, why risk even rebuilding with new seals and the hassle to go with it. I'm all for an engineering fix saving a few quid, but on brakes?? My fag packet maths shows about £100 difference between shiny new calliper with warranty and messing around rebuilding with seals??