Brake Bleeding Advice - Page 2 - ZR-1 Net Registry Forums

Tom · 12-19-2005

DOT 5.1 is a synthetic non-silicone brake fluid. I use DOT 3 brake fluid and change it once a year. Some track day events require you to have changed the brake fluid within so many days before the event, for example within 30 days of the event, to ensure the fluid has not had time to absorb moisture and reduce the boiling temperatures. You can look up most brake fluids at the manufacturers website and see what the new boiling point is. Different DOT 3's and 4's will have different boiling points, they just have to meet the minimum boiling point.

MINIMAL boiling points for these specifications are as follows:
Boiling Point Ranges
Dry Boiling Point Wet Boiling Point
DOT 3 205°C (401°F) 140°C (284°F)
DOT 4 230°C (446°F) 155°C (311°F)
DOT 5 260°C (500°F) 180°C (356°F)
DOT 5.1 270°C (518°F) 191°C (375°F)

WB9MCW · 12-19-2005

but now the big question is will dot 5.1 swell up the rubber parts??? if not then it would be a good fit 4 the ZR-1!! right??? posib. the dot 4's could work as well as no silicone too. But have not the Germans used reg dot5 in cars with ABS??? If so they why would the chev./gm say no go to dot 5.0 in the ZR-1 i wonder??? my mech still thinks the dot 5 is the way to go but he did admit to me he had never done an abs and was gonna check with his peer group guys on this and let me know!!!

Tom · 12-20-2005

The temperatures I posted above are minimums, if you look at premium DOT 3 and DOT 4 manufacturers data you will find they have dry boiling temperatures in the 500 deg range like DOT 5. If you use one of these premium fluids and change it regularly to keep the moisture content down you should get performance equivalent to the DOT 5. In addition since DOT 5 is not hygroscopic, any moisture that gets into the brake system will be free water with a boiling point of 212 deg.

I believe some DOT 5 containers have the statement "Not for use in ABS systems".

Converting to DOT 5 properly is a major job. You have to completely disassemble the brake system and replace every rubber component, all seals and rubber hoses, and completely flush all remnants of the DOT 3 or 4 fluid from all components including the brake lines or your boiling point will be whatever it was with the old fluid. Simply flushing the system with DOT 5 will not remove all of the old fluid since the seals and rubber hoses absorb quite a bit of the brake fluid. The old brake fluid will come out of the rubber parts until equilibrium is reached.

If you are concerned about seal swell you should use the fluid from the Chevy dealer that is listed in the owners manual since this is the fluid used in the certification tests for compatibility with the rubber components. ASTM D6546 gives the standard test method for performing swell tests when determing fluid/rubber compatibility. For a typical brake seal test you would weigh the seal in air, weigh the seal in water, immerse the seal in the brake fluid that would be installed in the vehicle, put the immersed seal in a 250 deg oven for a specified time, remove the seal from the fluid, rinse it off, and reweigh it in air and water, and then calculate the seal swell. Once this test is done you can place the seal on a sheet of white paper and see a large amount of fluid come out of the seal and form a ring on the paper and small drops on the seal surfaces.

bobbyhi · 12-20-2005

Way too technical for this old goat.............When I change mine I will probably go with the GM product recommend.

Hotrod · 12-20-2005

Becareful when using the vaccuum method for bleeding the brakes.. when the vaccuum is applied and the bleeder screw loosened, air can be sucked in around the threads of the bleeder screw and end up in the system!

WB9MCW · 12-20-2005

Thnx for the nice detailed post Tom! I think I will just stay with OEM fill, because as you point out, it is indeed and big ordeal to switch. Perhaps for the Auto-X-er it is worth the upgrade, just like most of em are upgrading the brakes anyway, so to go the extra yard on the fluids is no biggie! Sometimes the General knows best!!! LOL

tomtom72 · 12-21-2005

Quote:

Originally Posted by Hotrod

Becareful when using the vaccuum method for bleeding the brakes.. when the vaccuum is applied and the bleeder screw loosened, air can be sucked in around the threads of the bleeder screw and end up in the system!

Yes be careful of that. It is difficult to get the hang of not letting the air in around the threads of the bleeder screw. Next time I do it I'm going to have it done by a shop with the proper pres bleeder. I wasted too much time getting it air free to be worth the trouble. I finally used teflon pipe dope on the threads, carefully, to get a good seal.

Tom

Tom · 12-21-2005

I have been using the vacuum method of changing the fluid on my ZR-1 for almost 15 years. After the first time I changed the fluid I put teflon tape on the bleeder screws since I thought I was less likely to get the teflon tape where it shouldn't be than if I had used the teflon dope. The teflon also helps keep the bleeder screw from seizing in the caliper. I also put the teflon tape on the bleeder screws of my 1999 Firebird Formula the first time I changed it's brake fluid.

ralph92ZR1 · 01-05-2006

Thanks for all the advice; certainly learned alot about brake fluids. Am also now concerned about the "vacuum" method and potential of air intrusion at the bleeder valves; actually my friend has a C-4 and uses a vacuum pump but always had trouble with air.

Hate to beat a dead-horse but have you any recommendations on a pressure system. I tried Motive products but they are no certain on a ZR-1. Any advice in this area??? Its winter and I'm bored and really want to drain the fluid without hassles.

WB9MCW · 01-06-2006

RALPH if u a re a member of the zr-1 net/reg. in the (i think) fall newsletter Mark H.(who runs a specialty zr-1 shop in the western chicago sub's) had a very nice article on the special way he does the zr-1 cooling system including the 3 out of ten hard to do air entraped ones. He details a specific method to employ for the tough ones. It is restricted to the paid members only so I cant copy paste it here or give u a link(you need the pass word to get in the members section). So it is such: membership has it privilages!!! lo...l yes no doubt air entrapment is a PITA and any good mech. willl tell you they have their little secrets as to how to conquor the tough ones!!! Mark H. tell us his in the newsletter!

9-1-10 I see Ralph was asking about the "pressure brake bleeding system" not the cooling system... LOL silly me.

Well the info on the Marc H. cooling fluid replacement is well worth the read for you members Issue #4 Oct 2005

12-19-2005	#11
Tom Join Date: Jan 2004 Location: Southern CA Posts: 108	Re: Brake Bleeding Advice DOT 5.1 is a synthetic non-silicone brake fluid. I use DOT 3 brake fluid and change it once a year. Some track day events require you to have changed the brake fluid within so many days before the event, for example within 30 days of the event, to ensure the fluid has not had time to absorb moisture and reduce the boiling temperatures. You can look up most brake fluids at the manufacturers website and see what the new boiling point is. Different DOT 3's and 4's will have different boiling points, they just have to meet the minimum boiling point. MINIMAL boiling points for these specifications are as follows: Boiling Point Ranges Dry Boiling Point Wet Boiling Point DOT 3 205°C (401°F) 140°C (284°F) DOT 4 230°C (446°F) 155°C (311°F) DOT 5 260°C (500°F) 180°C (356°F) DOT 5.1 270°C (518°F) 191°C (375°F) Last edited by Tom; 12-19-2005 at 11:57 AM.

12-19-2005	#12
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,607	Re: Brake Bleeding Advice but now the big question is will dot 5.1 swell up the rubber parts??? if not then it would be a good fit 4 the ZR-1!! right??? posib. the dot 4's could work as well as no silicone too. But have not the Germans used reg dot5 in cars with ABS??? If so they why would the chev./gm say no go to dot 5.0 in the ZR-1 i wonder??? my mech still thinks the dot 5 is the way to go but he did admit to me he had never done an abs and was gonna check with his peer group guys on this and let me know!!! __________________ http://i119.photobucket.com/albums/o...9mcw/SIG-2.jpg http://i119.photobucket.com/albums/o128/wb9mcw/vcm.gif "The Budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome will become bankrupt. People must again learn to work instead of living on public assistance." - Cicero, 55 BC " We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution." - Abraham Lincoln

12-20-2005	#13
Tom Join Date: Jan 2004 Location: Southern CA Posts: 108	Re: Brake Bleeding Advice The temperatures I posted above are minimums, if you look at premium DOT 3 and DOT 4 manufacturers data you will find they have dry boiling temperatures in the 500 deg range like DOT 5. If you use one of these premium fluids and change it regularly to keep the moisture content down you should get performance equivalent to the DOT 5. In addition since DOT 5 is not hygroscopic, any moisture that gets into the brake system will be free water with a boiling point of 212 deg. I believe some DOT 5 containers have the statement "Not for use in ABS systems". Converting to DOT 5 properly is a major job. You have to completely disassemble the brake system and replace every rubber component, all seals and rubber hoses, and completely flush all remnants of the DOT 3 or 4 fluid from all components including the brake lines or your boiling point will be whatever it was with the old fluid. Simply flushing the system with DOT 5 will not remove all of the old fluid since the seals and rubber hoses absorb quite a bit of the brake fluid. The old brake fluid will come out of the rubber parts until equilibrium is reached. If you are concerned about seal swell you should use the fluid from the Chevy dealer that is listed in the owners manual since this is the fluid used in the certification tests for compatibility with the rubber components. ASTM D6546 gives the standard test method for performing swell tests when determing fluid/rubber compatibility. For a typical brake seal test you would weigh the seal in air, weigh the seal in water, immerse the seal in the brake fluid that would be installed in the vehicle, put the immersed seal in a 250 deg oven for a specified time, remove the seal from the fluid, rinse it off, and reweigh it in air and water, and then calculate the seal swell. Once this test is done you can place the seal on a sheet of white paper and see a large amount of fluid come out of the seal and form a ring on the paper and small drops on the seal surfaces.

12-20-2005	#14
bobbyhi Join Date: Jul 2005 Location: Mendota Heights, MN. 55120 Posts: 984	Re: Brake Bleeding Advice Way too technical for this old goat.............When I change mine I will probably go with the GM product recommend. __________________ Bob Anderson 1990 #2405 White/Gray Haibeck chip,4:09 gears,Power Effects Exhaust,5 spoke chrome,C5 brakes,49th Street rockers,K&N,Hurst,Headers,Upper & lower ported Minnesota State Director Founding Member #19

12-20-2005	#15
Hotrod Join Date: Sep 2005 Posts: 9	Re: Brake Bleeding Advice Becareful when using the vaccuum method for bleeding the brakes.. when the vaccuum is applied and the bleeder screw loosened, air can be sucked in around the threads of the bleeder screw and end up in the system!

12-20-2005	#16
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,607	Re: Brake Bleeding Advice Thnx for the nice detailed post Tom! I think I will just stay with OEM fill, because as you point out, it is indeed and big ordeal to switch. Perhaps for the Auto-X-er it is worth the upgrade, just like most of em are upgrading the brakes anyway, so to go the extra yard on the fluids is no biggie! Sometimes the General knows best!!! LOL __________________ http://i119.photobucket.com/albums/o...9mcw/SIG-2.jpg http://i119.photobucket.com/albums/o128/wb9mcw/vcm.gif "The Budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome will become bankrupt. People must again learn to work instead of living on public assistance." - Cicero, 55 BC " We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution." - Abraham Lincoln

12-21-2005	#18
Tom Join Date: Jan 2004 Location: Southern CA Posts: 108	Re: Brake Bleeding Advice I have been using the vacuum method of changing the fluid on my ZR-1 for almost 15 years. After the first time I changed the fluid I put teflon tape on the bleeder screws since I thought I was less likely to get the teflon tape where it shouldn't be than if I had used the teflon dope. The teflon also helps keep the bleeder screw from seizing in the caliper. I also put the teflon tape on the bleeder screws of my 1999 Firebird Formula the first time I changed it's brake fluid.

01-05-2006	#19
ralph92ZR1 Join Date: Dec 2005 Location: Shillington, Penna. Posts: 67	Re: Brake Bleeding Advice Thanks for all the advice; certainly learned alot about brake fluids. Am also now concerned about the "vacuum" method and potential of air intrusion at the bleeder valves; actually my friend has a C-4 and uses a vacuum pump but always had trouble with air. Hate to beat a dead-horse but have you any recommendations on a pressure system. I tried Motive products but they are no certain on a ZR-1. Any advice in this area??? Its winter and I'm bored and really want to drain the fluid without hassles. __________________ [FONT=Franklin Gothic Medium]Ralph E. Weise [/FONT]:) '92 ZR-1#473 Red/Red

01-06-2006	#20
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,607	Re: Brake Bleeding Advice RALPH if u a re a member of the zr-1 net/reg. in the (i think) fall newsletter Mark H.(who runs a specialty zr-1 shop in the western chicago sub's) had a very nice article on the special way he does the zr-1 cooling system including the 3 out of ten hard to do air entraped ones. He details a specific method to employ for the tough ones. It is restricted to the paid members only so I cant copy paste it here or give u a link(you need the pass word to get in the members section). So it is such: membership has it privilages!!! lo...l yes no doubt air entrapment is a PITA and any good mech. willl tell you they have their little secrets as to how to conquor the tough ones!!! Mark H. tell us his in the newsletter! 9-1-10 I see Ralph was asking about the "pressure brake bleeding system" not the cooling system... LOL silly me. Well the info on the Marc H. cooling fluid replacement is well worth the read for you members Issue #4 Oct 2005 __________________ http://i119.photobucket.com/albums/o...9mcw/SIG-2.jpg http://i119.photobucket.com/albums/o128/wb9mcw/vcm.gif "The Budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome will become bankrupt. People must again learn to work instead of living on public assistance." - Cicero, 55 BC " We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution." - Abraham Lincoln Last edited by WB9MCW; 09-01-2010 at 10:35 PM.