New Discs and Pads - Now spongy pedal

[rgracin]

Just replaced the discs and pads on my p2 V70 T5. I have put Brembo replacement discs with Ferrodo DS2500 pads.

Before, the brakes felt great with a high pedal. Now, they feel spongy. I can't see how any air got into the system. Any clues as to what might be the cause??

[fireclown]

hi new discs and pads will feel spongy until they are beeded in proply. take it for a steady run and apply the brakes gently. they will firm up.

[Goof]

You'll need to get some heat into them to help "cure" the pads - but don't go too mad, don't try to fry them too soon!
You may also experience from the gasses released during the curing process a feeling of sponginess and faded performance as the gas is escaping between the new pad and disk.
Bedding in new pads can be far more complex than just wearing off the rough bits so they fit the disk.

[rgracin]

I presume that with the harder pads, this proccess will take longer?

[Goof]

Probably.
Proper bedding in of new pads *can* help performance, wear rate and reduce brake squeal.
I'm not normally this techie on a subject - I have minor brake issues atm on my m/cycle, so typically I've Googled loads recently!

[t5tart]

Probably.
Proper bedding in of new pads *can* help performance, wear rate and reduce brake squeal.
I'm not normally this techie on a subject - I have minor brake issues atm on my m/cycle, so typically I've Googled loads recently!

best way to bed them in is to get to about 70 on a long straight road break hardis down to about 30 DONT STOP do this about 6-7 times then drive for a couple of miles to cool off the brakes before parking up then let them cool right off for afew hours then repeat the process all over again but being a biker you would know this from beding in bike brakes

its a matter of tempering the discs

[Goof]

best way to bed them in is to get to about 70 on a long straight road break hardis down to about 30 DONT STOP do this about 6-7 times then drive for a couple of miles to cool off the brakes before parking up then let them cool right off for afew hours then repeat the process all over again but being a biker you would know this from beding in bike brakes

its a matter of tempering the discs

Sounds like a normal run out for me - of course, I never get the bike above 70 anyway...


For those that are wondering why "Don't Stop" was in caps - stopping after that sort of use *can* lead to disk warp.
Similar to during a track day run - don't do several fast laps and pull into the pits and apply the handbrake as this has been known to cause disk warp, they need to be cooled without the pressure of a handbrake gripping a hot disk!
And, don't be tempted to touch them - they can reach 450+C easily ~ fingerprint stripping stuff! (Ok, who hasn't done it?...).

[t5tart]

doesnt even need to have the handbrake applied
the close prosimity of th epad to the disk on that section means it cools slower than the rest causing a warp sometimes

i know i have done it to brakes in the past

should really let the brakes cool after and use for a couple of miles b4 parking up anyway....... espoecially if say a dog has run out in front of you and you have had to use them hard...cause of corse no one would be going fast enuff to use them hard on pubilc roads unless it was an emergency

[GATHY]

Just replaced the discs and pads on my p2 V70 T5. I have put Brembo replacement discs with Ferrodo DS2500 pads.

Before, the brakes felt great with a high pedal. Now, they feel spongy. I can't see how any air got into the system. Any clues as to what might be the cause??

silly question but you have check you fluid level as when youve push your piston back all the way then fitted the new pad/disks and pumped the pedal back the fluid level drops again ? (

[rgracin]

Fluid level is fine. In fact, I had to drain some off.

[mraldonnelly]

Did you flush the system?

If not it would be worthwhile doing anyway. If any air did get into the system a flush should remove this and you'll also benefit from new fluid too.

Regards

Andy

[rgracin]

System is being flushed today in fact. I'll let you know how it all feels. Going to be doing a few miles in it next week which should help the bedding in process.

[mraldonnelly]

System is being flushed today in fact. I'll let you know how it all feels. Going to be doing a few miles in it next week which should help the bedding in process.

Did you get the fluid changed yesterday? If so, how's she feeling now?

Regards

Andy

[pyrotechnictigger]

Had exactly the same problem after doing mine. Spongy feel and I hate it! Had the fluid flushed and done with dot5. Not really done much, sniff

[rgracin]

Haven't driven it yet, New windscreen came, and was too small. but tha's another story. Now need to wear goggles!!. Closer inspection of the discs shows that they are only braking on two thirds at the moment, so I'm pretty sure they just need bedding in. Have only done about 50 miles since changing them. So only time till tell.

[mraldonnelly]

Haven't driven it yet, New windscreen came, and was too small. but tha's another story. Now need to wear goggles!!. Closer inspection of the discs shows that they are only braking on two thirds at the moment, so I'm pretty sure they just need bedding in. Have only done about 50 miles since changing them. So only time till tell.

Did you replace them yourself?

Are you sure the discs are seated straight? They should really be braking around the full diameter of the disc from the start.

It sounds to me as though either the discs are bent / warped or they're not seated correctly, perhaps as a result of dirt on the hub mating face or something.

Did you torque the wheel nuts up correctly?

Regards

Andy

[Babybadger]

You'll need to get some heat into them to help "cure" the pads - but don't go too mad, don't try to fry them too soon!
You may also experience from the gasses released during the curing process a feeling of sponginess and faded performance as the gas is escaping between the new pad and disk.
Bedding in new pads can be far more complex than just wearing off the rough bits so they fit the disk.

That gas will have a smell and that smell will be the fish smell then.......or was that the cat and the kipper on the front wheel.....

[Goof]

That gas will have a smell and that smell will be the fish smell then.......or was that the cat and the kipper on the front wheel.....

No! - all true I believe mate! - well, from what I've read elsewhere anyway.

[rgracin]

Did you replace them yourself?

Are you sure the discs are seated straight? They should really be braking around the full diameter of the disc from the start.

It sounds to me as though either the discs are bent / warped or they're not seated correctly, perhaps as a result of dirt on the hub mating face or something.

Did you torque the wheel nuts up correctly?

Regards

Andy

I did do them myself. All surfaces were free from foreign bodies, and smeared with copper grease. I think you may have misunderstood. The surface which already shows signs of wear if you like is three quarters of the disc from the outside towards the centre. Warping or incorrect seating would show via 'on off' wear around the disc.

Window should be back in today so I can get her back and let you know how it goes.


BTW, what is the correct torque setting for the wheel bolts. I've always gone by feel in the past, but I now have a shiny new torque wrench ready to go!

[mraldonnelly]

Ahhhhh, gotcha. Phew, I thought you meant around the diameter of the disc.

IIRC the torque setting is 110 something but I can't remember if it's nm or ft lb's without checking my Haynes manual. I'll have a look later and post it up if someone hasn't already done so.

Regards

Andy