Just read through this old thread, wondering if anybody has actually found exactly whats causing the psm/abs fault from the 27mm master ??

 

I just left psm disconnected and run the car like that since then, the braking response and feel is a better trade off for me . Would love to solve this if anyone got around it.

 

Yes thats the question, can id be done with psm activated ? I did this years ago on mine without psm, but want to hook it back up and get it to work correctly. Hopefully the guru's have found the answer to it, when hooked up it intermittently throws the 4460 and P1600 216 codes, very annoying

 

I reinstalled 27mm MC this summer. I have no issues whatsoever with CELs when driving on streets. But I get them immediately (=on first lap, after few corners) while at track, if PSM is on, causing both ABS and PSM to drop off. I have tried to find out what causes this without any hard data, but I assume that this MC builds brake pressure outside ABS/PSM's preprogrammed limits. And it's not just the pressure, I suspect that rate of deceleration, speed etc has something to do with this.
To fix the issue I have installed a switch inside the cabin to switch off the booster pump for trackdays. PSM light will come on and also this "Visit workshop" frequently, but ABS works just fine. When leaving for home I just switch the pump on before engine start and lights have disappeared. I also have changed the brake light switch and adjusted pedal to MC pushrod length. Now 6 trackdays without ABS issues.

 

I'm interested to see how this all works out for myself as I'm going to install the MC along with some GT3 PCCB calipers.
I swapped the stock calipers for a set of 7.1 GT3 ones last winter and had zero issues this summer at the track, so I'm interested to see what will happen when I move up a notch.
A picture of how you did the switch would be great?
Thanks

 

Nothing much to see about the switch, it's semihidden below the dash. I connected it as per pwdrhound's instructions and packed the harness again.
Big calipers and discs caused no problems in my car either, it's just that MC.

 

I am about to do the same and add a switch. I'm only getting the fault when the weather is hot and I've got significant heat in the brakes. I.e. - when I'm at the track. And I have found that disconnecting the psm completely provides an improved feel when at the track. Infact, I'm even disconnecting it when I'm racing in a straight line now, to stop the psm coming on at all.

 

I think the reason its so bothersome is that it should function without the error, the only thing the system sees is a increase in the volume vs the pedal travel, and even this may or may not be picked up by the sensors. We are enlarging the cylinder by aprox .070 of a inch, and the stoplight function is a direct on/off, not a sensor to speak of. Its been raining here lately so for the heck of it I took the car out on the wet smooth grass in the pasture with the PSM hooked up, abs and PSM worked flawlessly, and i pretty much went nuts sliding along a couple hundred feet with abs working, donuts, power slides ect ect. Everything functioned with no lights. (all in all great fun lol) However I suspect it will pop up again, till I find the correct cause.

 

ttt sure be nice if someone has ever found a answer to this issue yet ?

 

Lots of good info here: Post 293 onwards

I finally bled my brakes well and thorough, so I got that P4460 continuously with Master Warning. While no brake issues/warnings are not allowed in yearly state inspection I switched back to 6GT3 MC. Now it works again, and with switch in cockpit I still can switch the PSM completely off.

 

Reviving an old thread. I usually post on Rennlist and not much here but since this thread was helpful I'll add to the knowledge base.

I installed the 997 GT3 master cylinder in my 2003 996 C2 today. Yes I realize this is the TT and GT2 forum but the cars are similar enough and this thread was the most helpful one I found out there. My main goal was to reduce pedal travel and squishiness which I don't like when on the track in my 996.

The dual M12 ports on this master cylinder presented the same challenges to me that have been posted here before.

Unlike most of the cars posted here my car has the remote PSM booster pump way over on the passenger's side rather than under the master cylinder. This means that there is a very long brake line coming off the M10 rear circuit with lots of bends so I decided to use an M10/M12 adapter rather than make a line.

I found that there are two main M10/M12 adapters out there on the market, one made by Dorman and one made by AGS. Both have a bubble fitting on the male M12 end, but on the inside M10 female end they are milled to receive an SAE fitting, not a bubble (european) fitting going in.

I found that the Dorman adapter was a bit deeper on the M10 female portion than the AGS, so the Dorman one is the best one to use as it will engage the most threads.

I mounted the adapter under my drill press and using a 21/64" bit modified to cut brass, running at high RPM (2300) I turned the SAE female M10 internal surface into an internally tapered bubble (euro) surface. You can Google how to file a drill bit for cutting brass w/o gouging.

This worked out great and everything bolted up really nicely. I tested with very hard pedal pressure (standing on the brakes) several times w/ no leaks.

If you have the skills to do this it makes the install easy and the resulting reduced pedal pressure and travel is excellent!

Photos attached....

 

Seems like there finally is a fix for this issue, just bringing this thread up to hopefully help some guys on the psm light


https://www.6speedonline.com/forums/...r-psm-fix.html

 

Let’s see it.

 

posted the link its the next thread https://www.6speedonline.com/forums/...r-psm-fix.html