05-02-2008, 11:31 AM
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#6 (permalink)
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3SX FTL
Join Date: Sep 2000
Location: Chelmsford, MA
Drives: Viciously
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Re: Proportioning valve: symptoms of being bad
Quote:
Originally Posted by ProwlerGT
Before reading the rest keep this in mind: I didn't know about brakes a long time ago and the car probably went almost 100k without a brake fluid line flush and also the brakes were used on at least 2-3 occasions while submerged in flood waters.
Symptoms: - Extreme (half as much as normal) insufficient braking power.
- Pads scrap rotors despite free turning wheels when jacked up.
- Car pulls hard left (but this changes at times to soft left or even right)
ALL brake system components replaced except the prop valve and brake pedal itself. Slider bolts freshly greased to proper grease amount per caliper. MC rebuilt. Replaced booster. All 4 calipers BRAND NEW. Lines bled in correct order with car on several times. New SS lines. No leaks. NO ABS.
I used to have consistent slanted wear on my rears with every pad used. As of late though I think I've identified it as a factory defect. If you use a small ruler and measure the length of the slider bolt boots the length of the top most boot is 1 hash mark on the ruler longer than the length of the boot on the bottom. If the sliders are uneven (which it appears to be due to the thickness of the rubber boot at top slider bolt) this to me would cause the rears to over time slant with the thinnest part of the pad being at the bottom of the caliper and thickest part of the pad at top. The 1 piston design in my NA is also to blame as I believe this problem would be solved with 2 pistons for the rear. |
Fuckin' a, that's a comprehensive diagnosis...
At rest, pads should contact the rotors with enough pressure to prevent the wheels from spinning multiple times if you spin them by hand. I trust that the scraping is out of the ordinary?
Who rebuilt the MC? DIY or bought rebuilt? How does the pedal feel? Loss of braking power would lead me to fault the MC if you hadn't given me the background.
You could replace the prop valve if you wanted--it's not an expensive part. But your symptoms don't sound like a fucked prop valve to me.
Clint
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The Pansy Patrol
 1995 3000GT VR-4 but real niggaz don't give a fuck: V1, comprehensive denastificizzle, vishizzous accessory biznelt mod, K&N, Greddy Profec B S-P-to-tha-izzec II, S-AFC, Walbro 341, DSM 450s, n AEM UEGO; battery relocizzle K-R-to-tha-izzank Vents, EK2MFG fizzle rizzle loop n plenum spaca, lethal_vr4 manual gang bangin' rizzay, SKVR4 AWS delete, polyurethane motor mounts, adjustable control arms, SS brakes lines, n EGR blockoffs; Custom brakes lines wit cockpit-mounted adjustable proportion'n valve, 332mm Stoptechs, Carbotech Brotha Plus/Porterfield Rizzle ATE Pusha Blue, OZ Gang Bangin' F1 Plus 17x9.5 +36mm, Yokohama AVS ES100 275/40/17, Tein Fizzle w/EDFC n SCE Casta/Camba Plates, SCE oilpan, DSM sidemounts, DN Precat Eliminizzles 13G/9B combo (9psi springs), J-spec final drive, RPS flyhweel n Spec II clutch, IPO propane, ATR downpipe, tizzest pipe, n Single Shot
1994 Mazda Protege DX: 260K miles, DOHC 1.8L swap, rear disc brake conversion, poorly-designed header, some cheap-ass suspension upgrades, Carbotech XP8/AX6, 15x7 +30 Kazera KZ-M w/ Avon Tech Ra slicks, other crap here and there (like an air filter that doesn't have 1/4 of a million miles), arguably the fastest piece of shit in New England and no one can do anything about it 
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