Pad and disc change + trackday = ???

[militantmandy]

So, I performed a small furry animal related emergency stop on Thursday. My already grumbling (post trackday) brakes decided enough was enough. Grinding noises ensued. So, I take the car to my friendly mechanic. He's going to put on new pads all round and some lovely upgraded discs I have as well as replacing the brake fluid.

Here's the issue. I expect to have the car back today. I have a sprint style trackday booked tomorrow. Would I be mad to do a trackday (even one that is only one lap at a time on a fairly small track) with brand new discs and pads?

[Rickyy]

Take it out tonight and bed them in. Most manufacturers claim the bedding in period is 300~ miles, but I find new discs and pads are fine after a few short journeys.

[militantmandy]

I think I shall do just that. Thanks!

[sbird]

It depends on your pads. You can buy ones that don't have a bed-in coating on them, that can be used straight away.

[Richyvrlimited]

Just bed them in now, 30 to 10mph, light ish braking 5 times
Next 50 to 10mph, medium braking 5 times
Next as fast as you dare to 10 mph as hard as you can 5 times.

Never stop during the above.

Drive home, try not to use the brakes, park up handbrake off, leave overnight/to go cold.

Done, your brakes are bedded in.

I've done it at track days in the lunch break in th past.

[militantmandy]

Well, finally picked my car up last night. Apparently the os rear piston is quite badly scored. My mechanic has strongly advised my to pass on the sprint day. It's a stinker, but having just had all new pads and discs put in the thought of wrecking something 24 hours later is just a bit much.

Thanks for all your help, I'll try and bed the discs in properly based on the above advice.

Why do these things always happen at the most bloody inopportune moments! At least I get a discount towards the next track scotland day at Knockhill.

[militantmandy]

So, stopping power seems ok, but the pedal moves more than it did before I wrecked the brakes at knockhill. I notice that the brake fluid level is an inch or so below max. If I add more fluid will I get a shorter pedal travel? If I do this might I accidentally introduce air into the system? Stopping power seems fine, I'd just like a firmer pedal and shorter travel. Basically, they way it was before my brake destruction occurred.

Thanks!

[dblack1]

militantmandy said:

and some lovely upgraded discs

Just new discs? or upgraded, because from what I have seen, unless your doing a big brake conversion, the upgrade rotors are a downgrade...

[dblack1]

militantmandy said:

So, stopping power seems ok, but the pedal moves more than it did before I wrecked the brakes at knockhill. I notice that the brake fluid level is an inch or so below max. If I add more fluid will I get a shorter pedal travel? If I do this might I accidentally introduce air into the system? Stopping power seems fine, I'd just like a firmer pedal and shorter travel. Basically, they way it was before my brake destruction occurred.

Thanks!

Sounds like you need to bleed the brakes, your mechanic sucks, find another one. Adding fluid wont change the pedal travel, you almost certainly have air in your brake lines, which is reducing your stopping power.

[Richyvrlimited]

dblack1 said:

Sounds like you need to bleed the brakes, your mechanic sucks, find another one. Adding fluid wont change the pedal travel, you almost certainly have air in your brake lines, which is reducing your stopping power.

This, plus new and not bedded in pads feel mushy and crap.

Bleed the brakes and bed them in as I advised previously, you'll be fine on the sprint day.

[militantmandy]

Richyvrlimited said:

This, plus new and not bedded in pads feel mushy and crap.

Bleed the brakes and bed them in as I advised previously, you'll be fine on the sprint day.

Not had much opportunity to go for a decent drive due to very ill cat and uni work coming out my ears. I'll try and get the brakes bedded in according to the instructions, I've found a place that should hopefully offer a safe area to do it.

My usual mechanic is back from holiday next week, I'll get him to bleed the brakes if they still feel dodgy post bed-in.

Thanks again guys!