soft brake pedal with Big Reds
04-17-2009, 07:46 PM
#108
Rennlist Member
I have done quite a lot of research into the mushy pedal syndrome on our cars (or perhaps cars with Big Reds?), and I have also heard issues due to the hubs as well. In fact here are all the potential causes I've unearthed:
-wrong pads
-wrong fluid
-wrong lines
-wrong rotors
-poor cooling
-poor bleeding
-right hand drive
-wrong proportioning
-stock m/c
-loose hubs
and there's probably more I've forgotten about. I've addressed every one of these issues , except RHD as I found enough people with LHD who had the same issues.
Recently I found that switching to a drilled rotor seemed to help...but only for a short while. They cracked up pretty quickly (3 meetings) and the last meeting they seemed a bit worse again but that wasn't a soft pedal issue. Just a seeming lack of retardation. Also I had changed the pads out to some previously loved PFCs from the Pagid Blacks that I had in there before. Not sure why there wasn't the normal bite. Maybe the drill holes had become clogged with brake dust?
04-17-2009, 08:05 PM
#109
Former Vendor
Yeah the brakes have been great, but when a monkey does the work the hub gets ruined....arrghh...
IMO: Drilled rotors are a relic of the past that belongs in the past. Too many troubles.
IMO: Drilled rotors are a relic of the past that belongs in the past. Too many troubles.
04-17-2009, 08:20 PM
#110
Three Wheelin'
Join Date: Feb 2007
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drilled rotors are baaaaaaaad on track.
like said before, many reasons for a soft pedal, just gotto go at them 1 at a time.
cant wait to get my 996 setup on a friends volvo he found a slightly loost fitting near hyd brake... caused soft pedal all last year, but only 1 drop of fluid!
like said before, many reasons for a soft pedal, just gotto go at them 1 at a time.
cant wait to get my 996 setup
on a friends volvo he found a slightly loost fitting near hyd brake... caused soft pedal all last year, but only 1 drop of fluid!
04-18-2009, 01:18 AM
#111
Burning Brakes
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Interesting thread. Here's my thoughts of brakes in general after racing for 20 years.
- "Race Calipers" are relative. BB and BR would have been state of the art race calipers just 15 years ago, so you can call them "street" but again they are more than capable for most racers.
- A soft brake pedal can come from so many things, just as this thread is showing. If indeed its being caused by something pushing the pads back its easy to know. If pumping (softly) a couple of times before hitting them hard and find a firm pedal, then you've likely got something out of round. On most vehicles this is caused by warped rotors. However I'm sure its hard to warp these big rotors.
- ANY small deflection anywhere in the braking system is extremely amplified to the brake pedal. Many examples of this have been expressed here. Some are flexing in the firewall or pedal mounts, flex in the adapters etc.
- It is absolutely acceptable to adjust the fulcrum on your pedal. Any full race car with race pedals are infinitely adjustable. Of course common sense should prevail whenever a modification is made by looking at cause and effect.
- I personally find it hard to believe that 99% of 944 racecars need more than a BB or BR setup. The only reason you would want to go to that extreme is if you are overheating your brakes after ensuring you've done all you could to cool them properly. The only way I can see anyone doing that (overheating) is running some serious sized sticky tires up front.
No disrespect to other comments here, just my experience.
- "Race Calipers" are relative. BB and BR would have been state of the art race calipers just 15 years ago, so you can call them "street" but again they are more than capable for most racers.
- A soft brake pedal can come from so many things, just as this thread is showing. If indeed its being caused by something pushing the pads back its easy to know. If pumping (softly) a couple of times before hitting them hard and find a firm pedal, then you've likely got something out of round. On most vehicles this is caused by warped rotors. However I'm sure its hard to warp these big rotors.
- ANY small deflection anywhere in the braking system is extremely amplified to the brake pedal. Many examples of this have been expressed here. Some are flexing in the firewall or pedal mounts, flex in the adapters etc.
- It is absolutely acceptable to adjust the fulcrum on your pedal. Any full race car with race pedals are infinitely adjustable. Of course common sense should prevail whenever a modification is made by looking at cause and effect.
- I personally find it hard to believe that 99% of 944 racecars need more than a BB or BR setup. The only reason you would want to go to that extreme is if you are overheating your brakes after ensuring you've done all you could to cool them properly. The only way I can see anyone doing that (overheating) is running some serious sized sticky tires up front.
No disrespect to other comments here, just my experience.
Last edited by daigo; 04-18-2009 at 01:19 AM. Reason: spelling
04-18-2009, 01:30 AM
#112
Rennlist Member
Somewhat OT
My idea for going to an upgrade from BRs is based on a car that is not much lighter than stock, 285 slicks all round, 500+ horsepower. BRs used a pad that was never repeated again. Deep swept area towards the hub. Virtually all race brake and fast road setups have larger rotors with wider, but shallower swept pad area. This should apply a greater stopping power. With sticky and large front tyres plus a pretty heavy car with lots of power, I'm attracted to an upsize in brake capacity. I am also thinking of a Tilton type setup to go with it. I have a set of Cayenne TT calipers that I'm thinking of using.
I would still be interested in trying that fabled 7 Series BMW m/c as an upgrade. I bought one from Ebay, but it doesn't appear to look a lot like ours so fitting it may not be do able....or I was directed to the wrong one....
My idea for going to an upgrade from BRs is based on a car that is not much lighter than stock, 285 slicks all round, 500+ horsepower. BRs used a pad that was never repeated again. Deep swept area towards the hub. Virtually all race brake and fast road setups have larger rotors with wider, but shallower swept pad area. This should apply a greater stopping power. With sticky and large front tyres plus a pretty heavy car with lots of power, I'm attracted to an upsize in brake capacity. I am also thinking of a Tilton type setup to go with it. I have a set of Cayenne TT calipers that I'm thinking of using.
I would still be interested in trying that fabled 7 Series BMW m/c as an upgrade. I bought one from Ebay, but it doesn't appear to look a lot like ours so fitting it may not be do able....or I was directed to the wrong one....
