North American Turbocoupe Organization



Front end vibration
Ohio88TC Offline
Senior Member
#1
When I start coming to a halt under braking my front end vibrates like crazy. I am thinking that it is because my rotors are warped. It feel like it grabs and then doesnt and then grab again. When i put the brakes on all the way it is gone. Any ideas as to this. Also where is the cheapest for replacement rotors on the front. Right now I am trying to save ever bit of dime or does anyboy have a set of used rotors that aren't warped and in good condition? Thanks everybody.
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gddevil1 Offline
Member
#2
you may be able to have the rotors cut, if they are not severely warped. the wheel bearings may also be the culprit. If you are going to replace or have the rotors cut, you might as well replace them anyway. (they should be relatively cheap). IMO you shouldn't go too cheap on the brakes.....

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1988 tc-
3" atr downpipe
2.5" atr duals
k&n cone
Gillist Boost valve
centerforce clutch
all else stock..
for now
1988 tc-
3" atr downpipe
2.5" atr duals
k&n cone
Gillist Boost valve
centerforce clutch
3G alt. from Pa- performance
all else stock..
for now
NATO member
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Ohio88TC Offline
Senior Member
#3
I am pretty sure it isn't the bearings cause the front end goes up and down which to me means that it grabs and doesn't that is IMO the rotors are warped
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Pete D Offline
Administrator
#4
I'm not sure there are cheap rotors for these cars or that I would use them. I'm not a big fan of cutting warped rotors because my experience has been they just warp again and usually not too far down the road.

I have a set of relatively low mileage rotors but one of them is warped, that's why I replaced them. I'll sell them if you want to them, but like I say, they (it) may warp again

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, Main TC with K&N, 3"DP to 2.5"duals through Dynamax, Ric valve at 17+ and disconnected KS. Elite Bodega 16" chrome wheels. Autometer pod w/ A/F and Vac/boost gauges.140 mph Motorsports Speedo New engine: Total Seal rings and TRW pistons, ported and polished head w/ cc'd chambers,1.59"exhausts, SS valves, gutted upper, knife edged lower, A-230 cam, Race Engineering Adj Cam Sprocket, Crowlers, ARP head studs, and rod bolts. Walbro 255 HP pump and Kirban adj FPR, T-3. Centerforce II, KB subs and jack rails.
Pete Dunham


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Jeff K Offline
Administrator
#5
Are you sure it isnt some weird ABS problem, like the ABS is being applied at the front under light brake pedal application? As a quick test to rule out the ABS, remove the ABS main power relay to disable the ABS, and test drive the car. The power brake system is independant of the ABS part of the system, so you will still have power brakes if you try this, you just wont have the antilock function.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Ohio88TC Offline
Senior Member
#6
Just a quick question where is the ABS main power relay. Is that the one in the trunk on the back of the seats. Or do I disconnect it right at the pump on the brake master cylinder. You did bring up a good point there jeff thanks

[This message has been edited by Ohio88TC (edited 04-23-2002).]
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Pete D Offline
Administrator
#7
It's one of two relays directly under the vacuum tree on the fire wall. The other is the hydraulic pump relay for the brakes.
The one you want has 5 wires going to it and the colors are O/Y (orange w/ yellow), BR/PK (brown w/ pink), GY (gray), T/R (tan w/ red) and another GY

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, Main TC with K&N, 3"DP to 2.5"duals through Dynamax, Ric valve at 17+ and disconnected KS. Elite Bodega 16" chrome wheels. Autometer pod w/ A/F and Vac/boost gauges.140 mph Motorsports Speedo New engine: Total Seal rings and TRW pistons, ported and polished head w/ cc'd chambers,1.59"exhausts, SS valves, gutted upper, knife edged lower, A-230 cam, Race Engineering Adj Cam Sprocket, Crowlers, ARP head studs, and rod bolts. Walbro 255 HP pump and Kirban adj FPR, T-3. Centerforce II, KB subs and jack rails.
Pete Dunham


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Ohio88TC Offline
Senior Member
#8
I think that was the problem. I disconnected the relay and took it for a test drive around the block and it felt good. I know my sway bar linkage and bushing needs replaceing but it doesn't seem as violent now. I will know more after i drive home from work. If it is the relay any place that has this part to replace? I do like the anti lock brakes. Thanks Pete and Jeff
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Jeff K Offline
Administrator
#9
The ABS relay probably isnt the problem. My guess is you have a problem with the wheel speed sensors giving the ABS computer the wrong speed info, causing the ABS to activate. If the yellow ABS light isnt on, the ABS system thinks all is well, and you wont get any ABS error codes if you scan the ABS computer. Might want to be sure the ABS exciter rings are all clean and not full of crud, and that the gap between the sensors and the exciter rings is within spec. THis problem will be a real PITA to track down.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Ohio88TC Offline
Senior Member
#10
Thanks for the info and help Jeff. With these cars everything is a PITA [Image: smile.gif] but you still got to love them
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