Brake pads wear ?

[deanteam]

Was on a track day yesterday and had a good time. But checking after the car I noticed that the brake pads, after 40min. of track use (from new), had worn unsatisfactory. When I hold them together, they have worn V-shaped, on the top there is 3cm left when the two pads are held together, and 2cm on the bottom of the pads, they fit accordingly in the callipers. I use the Alcon four pot, now my question is, after checking the moving ability on the pistons and finding these fine, are the brake pads getting to warm on the trailing edge?

 

Regards Matthew

[Baby Bucket]

I too use Alcons, but haven't had this problem with Greens Stuff pads - although I did manage to cook them fairly comprehensively.

 

I suggest that you talk with James Whiting - would be grateful if you would let me know if he recommends different pads.

 

Cheers,

 

Peter

[Alex Wong1697456877]

I've found that Green Stuff pads wear very quickly.

[EFA]

You may have your calipers fitted upside down (i.e. on the wrong side of the car)

 

In a 4 pot caliper the two pistons are different sizes, large on the leading edge. The reverse may mean one end of the pad is effectively being worn faster.

 

The calipers normally have an arrow on to designate disc rotation direction.

 

 

 

Fat Arn

The NOW PROVEN R500 Eaterid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[deanteam]

Thanks for the replies.

I use green stuff, Alex so what kind of brake pads do you advice using?

According to your reply Arnie, the bigger Piston should be on the leading edge (does this mean that when they are on the car the bigger one’s are pointing towards the ground)? So due to the piston size area of the big piston I assume the travel Isn’t as much as the small one. So can I assume that as the leading edge will get hotter this will wear the pad by heat and the smaller piston with the bigger pressure capacity will wear this one by harder pressure? So if my explanation is correct this should wear the pads evenly? According to the arrow on the Alcon callipers then, they have been put together incorrectly, but this will mean that I will have to take them apart as the bleeding nipples will be on the bottom when I change them from one side to the other of the seven. Has anybody had this problem as well?

 

Regards Matthew

 

[EFA]

I'm not convinced I've got my leading and trailing edges the right way around.....Can anyone verify or do I need dismantle my brakes??? I'm now thinking the leading piston could be the smaller...... Peter C where are you???

 

If the arrow points in the same direction as the edge of the disc moves when the wheel rotates in a forward direction, you have them on the correct way round.

 

The nipples will always be at the top - it is also possible they have been assembled /machined wrongly.

 

 

 

 

 

Fat Arn

The NOW PROVEN R500 Eaterid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

[Blatman]

According to the Rally Design catalogue, Wilwood Technical Section, the calipers should have the smaller piston at the disc entrance, (ie nearer the ground!) and the larger piston at the disc exit.

The text says..."The larger piston end provides a slightly greater clamping force to compensate for pad taper that can occur under extended severe use applications. An improperly mounted caliper will cause increased pad taper and reduce overall braking efficiency"id=blue>

I'd be inspecting the brakes very carefully, and speaking to the vendor of said car or brake conversion.......

[deanteam]

Just put a picture on the web of the brake pads. Any comment on what could be the problem will help.

 

Thanks Matthew

 

http://home.sunrise.ch/deanteam/DeanTeam/brake_pads.htm

 

[Blatman]

From the picture, it seems like the calipers are on the right way round, so I can only guess at sticking pistons (the larger ones) or possibly an issue with too small a master cylinder not moving enough fluid. These are only guesses on my part though, sorry I can't be any more help sad.gif

[deanteam]

Update on this problem. We contacted James Whiting with the following e-mail, his reply follows. Is this what happens to all 4-pot systems when the pads are too soft?

 

Our e-mail:-

We recently fitted a new set of EBC green stuff pads into the Alcon

> brakes.

> > They were run-in on the road before being used for a sprint and a

circuit

> > session of 40mins. Inspection of the pads showed a large difference of

> brake

> > pad wear between the leading and trailing edges of the pads, at least

5mm

> > per pad. Both sides of the car showed the same wear rate. Since fitting

> the

> > later uprights the twisting effect previously reported has been

> eliminated.

> > The pistons were tested for movement and appeared to move freely.

However

> we

> > find that this wear is surprising considering that from your website the

> > information suggests that, quote:-

> > EBC Green Stuff material has been chosen for the kit after extensive

> testing

> > and provides good all round performance for road and track.

> >

> > I have attached an image of one set of pads to help explain the

situation.

> > We would very much like to receive your comments and recommendations.

 

 

James's response

 

Hi

> Hmmm.

> You are the only one (to our knowledge) with this wear problem ! I can

only

> suggest you try a harder material (Red stuff)

> Regards James