| ausmini https://www.ausmini.com/forums/ |
|
| Brake booster for Metro disks? https://www.ausmini.com/forums/viewtopic.php?f=2&t=4656 |
Page 1 of 2 |
| Author: | jill200sx [ Tue Feb 08, 2005 6:13 pm ] |
| Post subject: | Brake booster for Metro disks? |
I got the brakes bled today, and although they work the pedal is a little soft, you definitely couldnt call it a hard pedal. Im wondering (as WhoDat suggested  ) because I have the 4 pot calipers, does that mean the brakes pressure is divided over those 4 calipers and thus losing pedal hardness?
and would a brake booster help get back a firm/hard pedal? Whats involved in adding a brake booster to a 78 clubman that hasnt had one before? Thanks guys 
|
|
| Author: | aaron [ Tue Feb 08, 2005 6:25 pm ] |
| Post subject: | |
The front brakes arn't your problem, a soft pedal after you have had the brakes bled is from misadjusted, worn, dodgy rear drums. Adjust them up and see if thats any better. A brake booster only reduces how much you have to push the pedal to get equal force. I haven't got one,You don't need one, just push the pedal harder. Cheers Aaron |
|
| Author: | 13secmini [ Tue Feb 08, 2005 6:26 pm ] |
| Post subject: | |
i have the 4 pots on mine and have the same problem, very soft pedal till about 1/2 in then it starts to brake. I have a booster on mine but dosnt seem to help it. Im going to put a kit through my calipers next week and see if that helps, also give them a good bleed (repair a broken nipple). Another problem could be the master cylinder not upto pushing enough fluid for the 4 pots... |
|
| Author: | jill200sx [ Tue Feb 08, 2005 6:33 pm ] |
| Post subject: | |
the rear brakes were totally rebuilt also. machined drums, completely new pistons.. and the handbrake works sharp as, so I think the rears are fine.. not positive but pretty sure. My Metro calipers were totally rebuilt with new piston seals, I cant remember what else (*casual look for 3 page list of parts that went into Mini that I dont really want to look at again...) but all new bits... |
|
| Author: | aaron [ Tue Feb 08, 2005 6:35 pm ] |
| Post subject: | |
Strange... i would think that the master cylinder is (as 13sec said) the next thing to look at. Cheers Aaron |
|
| Author: | willy [ Tue Feb 08, 2005 6:36 pm ] |
| Post subject: | |
WHOA! Thats a mother of an avatar! |
|
| Author: | jill200sx [ Tue Feb 08, 2005 6:41 pm ] |
| Post subject: | |
 umm yeah, I thought it was resized automatically.. doh
new avatar muchas betterus
|
|
| Author: | brickworx [ Tue Feb 08, 2005 8:27 pm ] |
| Post subject: | |
A brake booster will make a firm pedal go soft.... only making your problem worse |
|
| Author: | Chris [ Tue Feb 08, 2005 8:49 pm ] |
| Post subject: | |
Is it a soft pedal or a low pedal? Brakes work by displacing a certain amount of fluid from the master cylinder, yes everyone knows this don't they? The displacement of the master cylinder is worked out to supply all cylinders with the correct amount of fluid before the pedal drops to far. If we add a 4 pot caliper(s) to the system does it require more fluid than the two pot? I don't know as I haven't seen them but if they require more fluid your pedal will always be low. A bigger bore MC will fix it if that is the problem. |
|
| Author: | brickworx [ Tue Feb 08, 2005 8:56 pm ] |
| Post subject: | |
any one? It's all about fluid flow from the master supporting the area contact of the caliper pistons. Bigger master... more fluid flow over a greater area but less pedal Smaller master... more pressure. |
|
| Author: | Chris [ Tue Feb 08, 2005 9:16 pm ] |
| Post subject: | |
brickworx wrote: any one?
It's all about fluid flow from the master supporting the area contact of the caliper pistons. Bigger master... more fluid flow over a greater area but less pedal Smaller master... more pressure. Are you sure? More fluid displacement for a given amount of pedal travel will = less pedal travel needed? The other problem becomes once the pedal linkage travels past a certain angle relative to the MC it starts to move the piston less (I think). If this is happening then the pedal pressures will rise for no more braking effort. |
|
| Author: | brickworx [ Tue Feb 08, 2005 9:21 pm ] |
| Post subject: | |
Now i'm going to have to check up at work tomorrow |
|
| Author: | justminis [ Tue Feb 08, 2005 9:27 pm ] |
| Post subject: | |
The 4 pots will use more fluid so the pedal will be low(er), but the pedal should be firm. I had 4 pots on my sprint mini (13sec's now) and the pedal was firm but low. When the caliper seals are very new, they can hold the caliper pistons back from the pads which translates into greater pedal travel too. Last time I rebuilt my S calipers this happened, a long pedal, but one lap around Morgan Park the pedal was back to where it should have been. Steve |
|
| Author: | jill200sx [ Wed Feb 09, 2005 5:00 pm ] |
| Post subject: | |
justminis wrote: The 4 pots will use more fluid so the pedal will be low(er), but the pedal should be firm. I had 4 pots on my sprint mini (13sec's now) and the pedal was firm but low. When the caliper seals are very new, they can hold the caliper pistons back from the pads which translates into greater pedal travel too. Last time I rebuilt my S calipers this happened, a long pedal, but one lap around Morgan Park the pedal was back to where it should have been. Steve
Im sorry guys, yes it did feel "soft" but when I got in it last night the pedal felt pretty damn good  I thought it had quite a bit of travel, but when I actually looked at my foot, it was more like 1", possibly a little more, travel. Sorry guys, false alarm.
I like justminis idea, a couple of laps around a track should sort it out  I was going to go for an early morning test drive to give them a decent workout, but I slept in (and I need the other engine mount before I can give it a real work out)
Next time I have it out I'll try and lock those brakes up, that will be the sure sign of their effectiveness. |
|
| Author: | 13secmini [ Wed Feb 09, 2005 6:01 pm ] |
| Post subject: | |
gave mine a good workout today on the track and must say they worked very well, first session they did not stop me at all (braking at 180kph at first corner),, but after i adjusted the rears and put some more fluid in they worked great, was hitting 180-190 with 100 meters to the corner and pulled up nice. |
|
| Page 1 of 2 | All times are UTC + 10 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|