What To Do With Clutch When Going DOT4

[NotYetLegend]

Quick question:

I have an HPDE coming up and plan on switching out brake lines, pads, and replacing the stock brake fluid with DOT4. Since our cars share the brake and clutch reservoir what do I need to do on the clutch side to make sure things are A ok?

Just not worry about it other than bleeding the clutch after doing the brakes?

Replace stock clutch line w/ stainless aftermarket one that wont deteriorate under DOT4 use?

Separate the two reservoirs and leave DOT3 in the clutch line as to not deteriorate the rubber o rings within the slave cylinder?

I know this question has been covered plenty on the forum (i did lots of searching/reading) but I found more contradictory information than I have on nearly any other topic on this forum. That makes me want to just leave the car as-is however there seems to be no contradiction that the stock fluid/lines/pads NEED to be switched to get the most out of your expensive track time. So I have to do SOMETHING, but what is the best way to go about this? Please help!

[The Stig]

You don't need to do anything. DOT3 and DOT4 can be mixed.

[NotYetLegend]

Originally Posted by The Stig

You don't need to do anything. DOT3 and DOT4 can be mixed.

Oh really! Well that's best case, I am very happy to hear that. Maybe the rubber deterioration thing was in regards to synthetic fluid (dot5?)? I don't know, whatever, that was all a nightmare.

So are the stainless lines required or just a might-as-well since you're in there? If they're not required I think I'll spend the extra bucks on better race pads (cobalt frictions seem to keep most people very happy) and dive into replacing the brake and clutch lines as budget permits.

Soooo many things to spend money on when you want to get more serious at the track. Looking at a used GoPro setup too so I can analyze my progress after the fact, happens to cost exactly what stainless brake lines do...

[karnov]

I would recommend doing the stainless steel brake lines. It is good performance gains for cheap(ish) money. I changed the pads, lines, and fluid on mine and am really happy with it. This combo has made a huge improvement in brake response and fade reduction, also in overall improvement in drive performance as I can brake much harder and later into a turn.

If you are going with a higher friction pad, then you'll likely make more heat than stock. If you want the most gain from your new pads, then change the lines along with the fluid and pads.

Also, just another recommendation on the SS brake lines... go with the good Goodridge G-stop lines. I have heard the cheaper ones leak. I went with the Goodridge lines and have had zero issues.

[NotYetLegend]

Originally Posted by karnov

I would recommend doing the stainless steel brake lines. It is good performance gains for cheap(ish) money. I changed the pads, lines, and fluid on mine and am really happy with it. This combo has made a huge improvement in brake response and fade reduction, also in overall improvement in drive performance as I can brake much harder and later into a turn.

If you are going with a higher friction pad, then you'll likely make more heat than stock. If you want the most gain from your new pads, then change the lines along with the fluid and pads.

Also, just another recommendation on the SS brake lines... go with the good Goodridge G-stop lines. I have heard the cheaper ones leak. I went with the Goodridge lines and have had zero issues.

Awesome thanks for the info. I'll just try to do all of it if I can afford too. Maybe skip the camera setup for now (kinda want one with car telemetry integration...) and put that money into ss lines. Really want to do the clutch line while I'm at it as well. What kind of pads did you end up going with???

[NotYetLegend]

Quick update: Just ordered everything I need from Amazon sans-pads for ~$230 delivered. I got the suggested Goodridge G-Stop lines, ATE 200 fluid (2X1 liter), brake caliper grease, flare nut wrench thingies (metric 3-piece), offset brake bleeder wrench and magnet bleeder bottle.

Now I just need to make up my damn mind about race pads and get those ordered up. Turning out to be much less expensive than I originally thought! gotta love it when that happens (very rare). Thanks again for the help guys.

[NotYetLegend]

Ordered Porterfield R4 pads (complete set) yesterday. With the 20% NASA discount this came to ~$325 which I think is reasonable. Will update after everything is installed and again after the HPDE weekend. Thanks again to everyone who helped steer me in the right direction.

[NotYetLegend]

Got the clutch sorted out. Did stainless brake lines but left the clutch line stock :(. Bled everything w dot4 (bleeding the clutch was kinda a pain...) And seems to be working great so far. Thanks to everyone who contributed!

[Bo White]

You need to put a remote rezzy on the clutch and cap the brake rezzy nipple off.

[NotYetLegend]

Yeah Bo, I considered that. Did the research and read what was available on the topic and I think I will do it eventually. My local track isn't crazy on brakes so I'll be fine for now however. I'll just keep bleeding regularly to make up for the systems shortcomings. Really want that fancy tic clucth line too, I'll make a project out of splitting the hydraulic systems and getting my clutch working better.

[Bo White]

#1 reason to have a remote rezzy is so the clutch doesn't contaminate the brake fluid.

[NotYetLegend]

Yeah that seems to be the census. I would also think that keeping the heat from the brakes away from the clutch would actually be more important in the immediate present when tracking, we all know how shit the stock clutch is when hot. I don't want the brakes heating up my clutch fluid!

[a7m1]

Originally Posted by NotYetLegend

Oh really! Well that's best case, I am very happy to hear that. Maybe the rubber deterioration thing was in regards to synthetic fluid (dot5?)? I don't know, whatever, that was all a nightmare.

So are the stainless lines required or just a might-as-well since you're in there? If they're not required I think I'll spend the extra bucks on better race pads (cobalt frictions seem to keep most people very happy) and dive into replacing the brake and clutch lines as budget permits.

Soooo many things to spend money on when you want to get more serious at the track. Looking at a used GoPro setup too so I can analyze my progress after the fact, happens to cost exactly what stainless brake lines do...

dot5 is for cars without abs it will break up your car i think it's sillicone based

dot5.1 is just like 3 and 4 just higher boiling point

you can safely go to dot5.1

you can save money and just keep the single reservoir and replace fluid every often

larger combined reservoir provides cooling

good luck

[Bo White]

Not near as much cooling as one would think. Vast majority of manual shift vehicles have remote rezzys. A larger clutch rezzy adds a little more cooling than a larger coolant rezzy which is none if any. The clutch contamination in the brake fluid is way more important to get rid of than the slight cooling aid a larger rezzy would provide. Not sure what the resistance is to separating the fluids.