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01-06-2009 | #1 |
Join Date: May 2005
Location: Leesburg, VA
Posts: 2,713
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Bleeding master cylinder question...
So I guess I'm a dope. I installed my DRM bias spring. Then followed the directions to bleed all four calipers, which took dangerous brakes (full of air) to merely insanely soft.
But I should have read the FSM instead. Apparently if you suspect the master has air in it, there is a procedure to bleed it first. However, I'd already bled the corners. Does that mean there may be air somewhere else in the system, like maybe in the ABS controller (pulled out of the m/c)? After bleeding the m/c tonight, I fired it up to feel the pedal with the booster. It's raining and at freezing so I don't want to drive it around, but the pedal feels more like normal, though not exactly firm. The manual actually says you don't have to bleed the calipers after bleeding the m/c if the calipers don't have air in them. I was surprised by that, but am I ok at this point? Or should I bleed the calipers for good measure? Or may there now be air in the ABS unit, and if so what do I do about it? Suggestions? Thanks!
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Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img] |
01-06-2009 | #2 |
Join Date: May 2007
Location: Peoria, AZ
Posts: 9,155
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Re: Bleeding master cylinder question...
Bob unless you power vacuum bleed the system its a crapshoot. So with that being said drive it around if the brake pulses while driving you have air in the system. If the brake functions feel the same I would not worry about it.
Which reminds me I need to do my spring from DRM via FU2 as my next project. How much a PITA was that?
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GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V |
01-06-2009 | #3 |
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Re: Bleeding master cylinder question...
You are supposed to bench bleed the master. Just undoing the lines from the master and screw in some adapters and running lines to the reservoir. The lines get minimal air in them while open as they are now the highest point in the system.
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01-07-2009 | #4 |
Join Date: May 2005
Location: Leesburg, VA
Posts: 2,713
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Re: Bleeding master cylinder question...
The snap ring is the biggest PITA. The spring has to be almost completely compressed and then you have to get the snap ring in there. It can be quick or take forever depending on your luck. I tried screwdrivers, socket extensions, etc to press the spring in, but nothing worked as well as my index finger. Unfortunately after about the millionth attempt, my finger was pretty beat up.
Hey Jeff, what do you mean about adapters? I just unscrewed the lines enough that fluid would run out as the brake pedal was depressed. Basically I (eventually) followed the FSM directions. Is there more to bleeding the m/c than that?
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Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img] |
01-07-2009 | #5 | |
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Re: Bleeding master cylinder question...
Quote:
Basically it seals off the port and does not allow any air back into the MC. |
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01-07-2009 | #6 |
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Re: Bleeding master cylinder question...
Thanks guys, this is right on time with my bias spring on the way and all new brake system on my Z after this long storage.
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01-07-2009 | #7 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Re: Bleeding master cylinder question...
..... if you have a spare slave cylinder use the bleeder from it, that works at the larger of the two M/C lines. The smaller of the two @ the M/C takes a caliper bleeder screw....get some rubber tubing & you're in like flint.
I do believe that on the 90 abs system, unless the system is actually used the air you have can not get into the pump. During the self tests, it just works the solenoid valves to make sure they work.....I think I'm correct... It is easier on a bench in a vise. I made a tool from an old slave cylinder push rod fitted into a small block of wood for a hdl...fits the M/C piston like a glove. tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
01-07-2009 | #8 |
Join Date: May 2005
Location: Leesburg, VA
Posts: 2,713
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Re: Bleeding master cylinder question...
What would prevent air from getting in when you remove the adapters to re-install the brake lines?
I didn't remove my m/c from the car. I followed the DRM instructions and picked the proportioning valve out vs beating it against some wood like the FSM suggests. Thanks for the feedback everyone. I think I will just drive the car (tomorrow should be a nicer day) and see how it feels. If it's not good then I'll bleed all the calipers again.
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Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img] |
01-07-2009 | #9 | |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Re: Bleeding master cylinder question...
Quote:
Also, I was always taught that unless you use a p-bleeder, any M/C work needs to be bench blead to negate the risk of bottoming out the M/C piston at the end of the bore & possibly damaging the piston seals when ya bleed it in the car. Actually, I did have to do a few sharp wacks, used my bench bleeder tool to smack the mount flange a few times and then a coupla hits on the oak block....it came out but it took some right sharp raps. I thought I was gonna break the thing. tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
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01-07-2009 | #10 |
Join Date: Nov 2006
Location: dayton,ohio
Posts: 425
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Re: Bleeding master cylinder question...
I've bleed mine several times by getting a spare MC cap and seal, put a NPT fitting in it and putting 8 psi on the MC, it can be done pretty quick. It needs a hose clamp around the cap also and will still pop off above 10 psi. But if your worried about a brake fluid mess if the cap pops off, mine didn't and it's popped off probably 5 times when I was trying to find the maximum limit. I know some claim gravity bleeding works good, just take all day.
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[FONT=Comic Sans MS][COLOR=red]"I wanna go fast!!"[/COLOR][/FONT] [FONT=Comic Sans MS][COLOR=#ff0000]-- Ricky Bobby[/COLOR][/FONT] |
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