TPink

From reading prior posts it seems that brake pads/rotors/fluids/cooling aids are a package that should match one's driving habits and the car's HP. So I have some questions in my case and would appreciate the Rennlist's guru's comments:

I have a 77 911S with an 85 3.2 engine. I run in green/yellow group for DE 2-4 days a year (would love to do more, but you know....). After 12 years of owning this car (and 60,000 miles, which tells you how hard I drive in DE) I am changing rotors to ATE PowerDisc orbital slotted in front; Zimm vented in rear.

Rotor question: I would think the above "upgrade" will meet my street and DE needs through yellow into white groups. Do I need anything more in this area?

I changed pads 3 times in that time frame. Again, for street and light/med DE use I just ordered Mintex for F/R. Any comments,concerns here as well from those who are familiar with other pads?

My real question is on brake fluid. Are the DOT 4 ATE Super Blue/200 and high-end Castrol too much for mostly street and light/mod DE driving?
I am leaning toward Castrol LMS DOT 4 since it absorbs less moisture as I do not want to be changing fluid 3x a year. I THINK I am driving nowhere near the limits of this fluid temp. even during DE events and therefore do not need racing fluid (that seems to require more frequent changes). Any thoughts on what is best for street/casual DE use vs. race fluid?

Finally, when bleeding brakes, is the power bleeder much better than my older bleeder kit that attached to the caliper?

Thanks!!!!

Chris Martin

I have been using ATE super blue fluid mostly on the street for about 2 yrs with no issues. Since you should bleed the brakes before every DE anyway I dont think you will have any problems with this fluid. Besides, I dont think it retains any more moisture than other fluids. It's not silicone based.

I like the Motive Power bleeder, but it's just personal choice I think. I have heard that suction type bleeders can have problems getting small air pockets out, but have not had this problem.

I think you only need to upgrade when you have a problem or find a limitation. If you have good success with your current setup why change? On the other hand if you notice brake fade or subpar braking then you should look at your setup. For high speed tracks you might think about a brake cooling kit for the front, but I would wait to see if you need it first. For what you described it sounds like your configuration should work out great.

Bill Gregory

Well, those questions cover alot of ground. In order:

I would upgrade your brakes to the Carrera 84-89 brakes. Better heat sink capacity and better brake matchup with the 3.2L engine capacity to propel you forward. They are available used and cheap from people upgrading to yet larger brakes.

The ATE powerdiscs are good slotted rotors - I used them on my SC. Stock rotor in the rear is fine.

As far as improvements, you want to keep things cool and use a good brake fluid. Look at one of the brake cooling kits that installs under your a-arm and pipes air into the eye of the rotor. Also, if you have Fuchs, you'll want a piece of metal to close off the gap between the hub and wheel to keep air from flowing right out. The OG Racing cooling kit comes with that part. I believe it's extra with the Weltmeister kit. Smart Racing makes a nice stainless set for around $35. As for brake fluid, no fluid is "too much", well, maybe Castrol SRF is too much, but it has it's place too. Stick to the ATE Super Blue/Typ 200, it's a very good brake fluid, better than the other Castrol fluid you mentioned.

For bleeders, I much prefer the power bleeders to the vacuum ones at the caliper. However, if you have a vacuum one and it works for you - great. The goal is the same

TPink

Thanks for the above imput. I had more ?'s, but did not include it above. I am also changing the brake lines in the front. Not to steel, but rubber.

Are there any tricks to changing the brake lines and rotors in a 77 911S?

Thx

Chris Martin

Changing the brake lines is pretty straight forward, but be ready to buy a few extra parts. I replaced the lines on my SC and found 3 of the 4 metal lines needed to be cut off as they were completed siezed to the flexible line. Just a heads up. Also, might as well replace/repack the front wheel bearings when you have them off. The pelican site has a good diagram of the brake lines and the appropriate clips and so on.

Bill Gregory

[quote]<strong>Also, might as well replace/repack the front wheel bearings when you have them off. </strong><hr></blockquote>

That's a good idea. You will need to replace the rear grease seals when you repack the inside bearings. It's Porsche part number 477.405.641. You'll need two, one for each side, and they aren't expensive.

TPink

Oh no, I knew this would happen! That's it, I am selling the car!!!

I will be lucky if I can drive it home! LOL

Actually, I have done brakes before, but not wheel bearings or brake lines, so I am a bit apprehensive about doing those repairs. I am trying to get the car ready for 2 days at LRP Aug 23/24.

TPink

sorry to bring this up again...

I just received my Powerbleeder and was trying to bleed the brakes. I have a 77S that has a drain valve in the bfluid reservoir. When I pressurize the system it just blows brake fluid out the drain valve (a plastic tube coming from top of reservoir and exits just behind front spoiler on driver's side). I should have remembered that!

Is this a common problem with other years and how to solve? Should I attempt to plug that valve or forget bleeing brakes with a pressurized system (either use mityvac at wheels or the old 1-2 pump and tighten bleeder valve)?

Bill Verburg

I agree with Bill G. that at a minimum the upgrade, at least at the front, to 84-89 Carrera brakes should be done. Sloting/drilling doesn't help cooling at all, it does help keep the surfaces in solid contact by keeping them free of debris. Here is a page with various mods layed out for you <a href="http://home.nycap.rr.com/wmv/generalbrmd.htm" target="_blank">Brake mods</a>

I suspect that 930 size brakes may be in your future though.

Definitely upgrade to the best fluid you can afford and change it regularly. Here is a page which has various b/f specs <a href="http://members.rennlist.com/911pcars/brakefluid.htm" target="_blank">Brake fluid comparison</a>
Also make an effort to duct cool air to the rotor throat. Here is a nice writeup about that <a href="http://www.pcasd.org/tech/tech_may.shtml" target="_blank">Brake cooling</a>

Bill Gregory

[quote]<strong> When I pressurize the system it just blows brake fluid out the drain valve Is this a common problem with other years and how to solve? Should I attempt to plug that valve or forget bleeing brakes with a pressurized system (either use mityvac at wheels or the old 1-2 pump and tighten bleeder valve)?</strong><hr></blockquote>

You do need to plug that line to prevent fluid from ending up on the floor. If it's a solid plastic line to the floor, do what later 911's do and that's cut into the line, and add some rubber or braided rubber hose with two hose clamps. Then you can easily use a locking wrench, or whatever, to close off the flow. Pressure bleeding works fine, I pressure bleed my brakes maybe 15-20 times a year, and it works no problemo.

Suggest you NOT use the significant-other-pump-the-brakes method of bleeding if you have an older master cylinder. This method of bleeding pushes the master cylinder seals into areas that are corroded and don't normally see any movement. This rips the seals, guaranteeing a new master cylinder in the near future.

TPink

mucho gracias!

I thought there was a solution!
My S/T need is brake flushing for DE.
I am on the fence of either upgrading only rotors/pads over OEM, or upgrading brake systems to either 930 or 84-89 911. I do like matching the bigger calipers to the 3.2/bursch.

I guess upgrading brakes systems be a better match should I chip the 3.2 in the future, should I drive well enough at DE to handle that speed!

Tom