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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Jun 28, 2016 6:57 pm Post subject: |
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The front brakes are behaving similarly with deep pedal before grabbing at all. Pad position is perfect.
I have a tool on order that will let me measure the length of the booster rod. No matter what the reading, I don't see any way to adjust the rod depth if it is too short. What do people do? Cut a spare rod and put the plug down in the hole? If I do that then the grooves in the rod will move forward. Anybody know what those grooves are for? |
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chevymad Master B
Joined: 11 Jan 2004 Posts: 5474
1987 Pontiac Formula
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Posted: Tue Jun 28, 2016 7:46 pm Post subject: |
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You have the calipers on the right sides?? You seriously wouldn't believe how many times i've seen that done. They bleed and bleed the brakes.. no air of course and no pedal. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Tue Jun 28, 2016 8:45 pm Post subject: |
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Yes, but I don't like the location of the bleed port on the PBR rear calipers. They go out the side and don't look optimized (dead at the top). I don't have x-ray vision inside the caliper but it doesn't look quite right from the outside.
I see on a C4 Corvette that the calipers are in the 10:00 position, whereas mine are in the 4:00 position. Mine are flipped so the bleed valve is on top but I might pull the calipers off the brackets and rotate higher when I bleed. |
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Twilightoptics Hardcore (12sec Club)
Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jun 29, 2016 9:17 am Post subject: |
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If the pedal doesn't firm up with the engine off, forget the booster for now. _________________ A redline a day keeps the carbon away! |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Wed Jun 29, 2016 6:20 pm Post subject: |
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I couldn't find a master cylinder plug anywhere so I fabbed up a couple short brake lines with enough adapters to make a plug. With both ports plugged the master cylinder is firm and the pedal is hard right at the top.
So.... we're down to air in the system either from inadequate bleeding, a leak, or malfunctioning caliper. I guess I'm going to learn a new method of bleeding. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Wed Jun 29, 2016 6:47 pm Post subject: |
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I'll be darned. The brake pedal is high after hooking up the lines again and I haven't even bled it. I must have had air in the lines going to the master. Now I just need to get really smart about bleeding the whole system and I hope things will be wonderful! |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Wed Jun 29, 2016 7:54 pm Post subject: |
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Good solve, Jon. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Wed Jun 29, 2016 8:16 pm Post subject: |
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Ya, other than the $70 rod depth tool that will show up on my porch any day now. Hope there is a return policy on that.
Speaking of boxes, I've been getting a lot of boxes lately in prep for a cam swap. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Thu Jun 30, 2016 6:23 pm Post subject: |
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Brakes are a lot better now. But rear brakes still aren't participating as much as I want.
Also, I wish the pedal was harder to push because I find I can lock up the front brakes fairly easy. I want to have to stand on the brake pedal harder before locking. It will work better with the body's natural reaction in an emergency. Maybe I'm a manual brake kind of guy.... |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Thu Jun 30, 2016 8:09 pm Post subject: |
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Time for the old-school 7" chromed out booster?
Only partially a joke, that might give you a less boosted feel.
Rear brakes is just prop valve adjustment unless you still have some air back there. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Thu Jun 30, 2016 9:31 pm Post subject: |
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No, the prop valve is at max pressure. Bottom line is I simply have too much front bias and the rear will never lock up.
* I can either lose the drag radials for less sticky tires (not going to happen)
* put stickier tires on the front
* load the rear brakes with some mega grippy pads
* load the front brakes with less grippy pads
I'm going to play with pads. It will improve overall stopping performance and distance. Although, sticky front tires would take it to the next level and haul down like a race car. |
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Dewey316 The Lama
Joined: 08 Jan 2004 Posts: 7295 Location: Bringing the tech
1990 Chevrolet Camaro RS
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Posted: Fri Jul 01, 2016 6:28 am Post subject: |
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How exactly is this all plumbed, and what prop valve are you using?
My gut says, you kept a prop valve, and then put the adjustable valve inline on the rears. In which case, you can never go above factory rear line pressure.
Bypass the prop valve so you have no rear line pressure drop, then put the adjustable valve inline on a full pressure line, then you will have full rear line pressure and can use the valve to drop it to a pressure that works for you. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Fri Jul 01, 2016 3:09 pm Post subject: |
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QwkTrip wrote: | Yes, original prop valve is gone. |
You're 4 days behind, bud. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Fri Jul 01, 2016 10:28 pm Post subject: |
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A co-worker had a good suggestion to swap front and rear tires and see what happens. If the rear brakes are working well then I should get lock up. If not, then I should measure for low rear line pressure. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Fri Jul 01, 2016 11:21 pm Post subject: |
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I finally found a parking spot at work that seemed okay.
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chevymad Master B
Joined: 11 Jan 2004 Posts: 5474
1987 Pontiac Formula
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Posted: Sat Jul 02, 2016 10:06 am Post subject: |
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Looks good, other then the creepy old guy hovering near it. You should shoo him off. |
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Twilightoptics Hardcore (12sec Club)
Joined: 13 Jan 2004 Posts: 9191 Location: Auburn , WA
1987 Chevrolet Camaro IROC-Z
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Posted: Sat Jul 02, 2016 10:23 am Post subject: |
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They painted the parking spots too small...
Car looks good. _________________ A redline a day keeps the carbon away! |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Sat Jul 02, 2016 11:20 am Post subject: |
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chevymad wrote: | Looks good, other then the creepy old guy hovering near it |
That was right after eating a burrito and driving with the windows down on the freeway. Probably not a good moment to take a picture in hindsight. |
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aaron_sK Member
Joined: 23 Jan 2006 Posts: 8834 Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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Posted: Sat Jul 02, 2016 5:31 pm Post subject: |
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Short sleeve collared shirt on an engineer, story checks out. Solid beard too.
The car looks amazing. I'm liking those wheels more and more. |
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QwkTrip 11sec Club
Joined: 17 Feb 2004 Posts: 3942 Location: Peoria, IL
1989 Pontiac Firebird
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Posted: Sat Jul 23, 2016 6:36 am Post subject: |
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Hopefully this will make the engine pull better on the top end. Also got upgraded rocker trunions that I will install at same time.
Last edited by QwkTrip on Sat Jul 23, 2016 6:37 am; edited 1 time in total |
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