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Topic: Not quite Brake Hell II, but....

in Forum: C3 Engines, Driveline and Handling


Not quite Brake Hell II, but....

Posted: 7/26/04 4:41am Message 1 of 8
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Clifton, NJ - USA
Joined: 10/3/2003
Posts: 129
Vette(s): 1972 Coupe Ontario Orange Black leather interior LS-5; Turbo 400
Ok, I'm thinking I'm so far in to this problem that I can't see the forest for the trees. My 72 coupe sat for about 6 years, and as I awoke it, the brakes had disappeared. Translation: pedal went to floor, no braking at all.

Ok, so I rebuilt all 4 calipers, installing VB&P's O ring conversation kit, 4 new rotors (the old ones appeared to be original), and a new mater cylinder from Corvette Central.

Now the pedal goes almost all the way to the floor, and barely holds the car at idle in forward or reverse. The brake warning lamp is functional, but does not illuminate when I press on the pedal, indicating to me that the proportional valve is not an issue. I have not taken it out on the street, as I feel decent brakes are a good thing!

I have bled those puppies by gravity first, then via the pedal approach until NO bubbles appeared, then I went around and tapped on each caliper with a rubber malet to dislodge any trapped bubbles. Then I bled them again and saw little or no bubbles. No leaks apparent anywhere.

Other than the power poster, any ideas? I thought when the booster goes bad, pedal effort increases, which is not I case I find. I will checking the length on the adjustable rod that transmitts the action from the booster to the M/C vs the spec.

Any and all suggestions ( as they relate to my problem) will be greatly appreaciated.

Thanks

NJ BB Ken


|headscratch|


1972 T Top 454; "Boomer" Latest "upgrades": 1 1/8" front Stabilizer bar. Rebuilt SS calipers with O-ring pistons. Under car Chambered exhaust. Fiberglass rear spring (360lbs/in). Bilstein Rear Shocks. 3/4" Rear Stabilizer Bar. Tow hitch. Performer manifold with 600 cfm Holley. Comp Cam 262 .499 lift. L-88 Hood in process

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Not quite Brake Hell II, but....

Posted: 7/26/04 8:48am Message 2 of 8
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
how about the brake hoses.. they could have rotted..

have someone push the pedal while you check and see if they are swelling.


Not quite Brake Hell II, but....

Posted: 7/26/04 9:54am Message 3 of 8
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North Hills, CA - USA
Joined: 6/12/2003
Posts: 515
Vette(s): 1972 T-Top
I had to go through the gravity sequence 3 times to get good pedal pressure. Tap on the caliper with a rubber mallet when you first start the bleed. I also gave it a slight push with the pedal to get it started on the first round. Bleeding these brakes can be frustrating, but don't have your wife pump the pedal for you! haha!
Reid '72 T-top |idea|



    Reid    '72 T-top

www.wildbunchcarclub.com

www.vannuyscruisingassociation.com


Not quite Brake Hell II, but....

Posted: 7/26/04 10:12am Message 4 of 8
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Clifton, NJ - USA
Joined: 10/3/2003
Posts: 129
Vette(s): 1972 Coupe Ontario Orange Black leather interior LS-5; Turbo 400
Thanks guys;

I had installed SS braided hoses when I installed the SS sleeved calipers when I first got the car ('88).

This is most frustrating, as I essentially did the same things to my '67 roadster, and had pretty good brakes as a result!

As the Stones once said, "Let it Bleed!"

Cheers

NJ BB Ken |cheers|


1972 T Top 454; "Boomer" Latest "upgrades": 1 1/8" front Stabilizer bar. Rebuilt SS calipers with O-ring pistons. Under car Chambered exhaust. Fiberglass rear spring (360lbs/in). Bilstein Rear Shocks. 3/4" Rear Stabilizer Bar. Tow hitch. Performer manifold with 600 cfm Holley. Comp Cam 262 .499 lift. L-88 Hood in process

Not quite Brake Hell II, but....

Posted: 7/26/04 9:14pm Message 5 of 8
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
i assume you beld the master cylinder..

i prefer actively bleeding the brakes..

i used a pair of those speed bleeders recently and they rock.. the easiest ive ever done..

you might try to screw those little plastic fitting from a master cylinder bleed kit into it.. bleed the master cyl.. then leave it over night..

rebleed it in the morning and see if there is any air in the MC. if not the MC is ok..

use brass fittings and block off all the brakes but one. bleed it.. tap on it with a hammer.. let it set for a few hours.. rebleed.. any air..

repeat with each wheel until you find the leak.


Not quite Brake Hell II, but....

Posted: 7/27/04 4:44pm Message 6 of 8
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Australia
Joined: 5/6/2004
Posts: 535
Vette(s): 71 Coupe Black on Black
You probably know this anyway but make sure not to pump the pedal to fast when manually bleeding. It can cause the fluid to aerate and you'll never get all the air out. |hammer|


Not quite Brake Hell II, but....

Posted: 8/3/04 2:56pm Message 7 of 8
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Joined: 5/5/2004
Posts: 6
Vette(s): 1972 Corvette Convertible 3rd Owner
So, how have things turned out for you?

I'm having a similar problem. I've gone through all the same steps, but still have a soft pedal (not as bad as yours though). I'm waiting to see how things work out for you before tackling my problems. My brakes still stop adequately, but not as well as I think they should.

Keep us posted!!

Thanks - Al


Not quite Brake Hell II, but....

Posted: 8/9/04 5:52am Message 8 of 8
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Clifton, NJ - USA
Joined: 10/3/2003
Posts: 129
Vette(s): 1972 Coupe Ontario Orange Black leather interior LS-5; Turbo 400
OK, Partial update time.

I have completed the replacement of the power brake booster, it was not as bad as I thought it was going to be, but then I removed the driver seat and the steering wheel to allow the easiest access under the dash. ( I strongly reccomend this to anyone attempting to replace their booster!) Even with the easier access my lower back is barking a bit today!

The brakes feel better, although I am in the process of installing the Reflectix insulation in the driver side, and have not sat in the seat and depressed the barkes with the engine on yet. As with most projects on a 32 year old car, You start out to replace "A", and you find you also need to address "B", "C", & "D"!!!

So, when I removed the driver seat, I discovered the carpeting was shot, so I ordered up a set from Wilcox Corvette parts. Having heard the good opinions on the value of installing the Reflectix, I went out and got roll of the insulation from Lowes. I should have the Driver side finished by the weekend, so I'll post my brake status then. Before I give it the once around the block test, I intend to give the brakes one last Vac. bleed with my Mini-Vac pump.

I finally got my Collectors Insurance, so the Historic Plate application goes in today!! |bouncy|

I hope to actually do some damage out on the street with the car before the glaciers return this winter.

|cheers|

NJ BB Ken


1972 T Top 454; "Boomer" Latest "upgrades": 1 1/8" front Stabilizer bar. Rebuilt SS calipers with O-ring pistons. Under car Chambered exhaust. Fiberglass rear spring (360lbs/in). Bilstein Rear Shocks. 3/4" Rear Stabilizer Bar. Tow hitch. Performer manifold with 600 cfm Holley. Comp Cam 262 .499 lift. L-88 Hood in process

in Forum: C3 Engines, Driveline and Handling


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