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Driver Rear Brake Hanging


07SGT5687
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So I finished up the Whipple install and took the car our for her maiden voyage last night. WOW, btw... ooofda.

 

Anyway, at about 65mph, I notice a vibration from the rear and when I stopped I noticed a PRONOUNCED brake smell from the driver rear caliper. Went back home, put it up on jacks and went to bed. Going to look into it tonight, but in advance of that, does anyone here have any idea what the case could be? I recently swapped pads, but I've done that plenty of times and this last time I actually had the proper caliper retractor tool for once. Just wondering if you all can provide any insight as to what might be the problem before I start looking at it. Not really sure what could be wrong. Only 10k on those calipers. :headscratch: SO frustrating! I want to get that Whipple out on the road!!!

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Anyone? This is killing me! I cannot for the life of me figure out what is going on. I put the rear up on jack stands, took the calipers apart, fully retracted the cylinders, reseated the pads, they spun freely, I depressed the brakes and they are dragging again? Seems like the calipers are not retracting fully. Pardon my ignorance, but when you fully let off the pedal are the cylinders supposed to fully 100% retract? I'm not knowledgeable enough about brake systems to know. This is killing me! I want to get this thing out of the garage now that the SC is installed. ARGH! :censored::angry22::rant2::banghead:

Edited by 07SGT5687
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When you put this back together and pumped the brakes to set the pads and the spun the rear axle by hand how much drag did you feel. Does it feel the same all the way around rotating the wheel 360 degrees?

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How do you mean SEAT the pads?

 

 

 

Seating or "bedding in" is the slow application of brake pressure and heat--vice a rapid application. From the sounds of things, you didn't replace the pads with the supercharger application, right? If the brakes had some time on them prior to the s/c install, then the bedding in shouldn't be the cause. If they were new with the s/c install and you really got on them without bedding them in, then perhaps the warped rotor is a chance.

Then, again maybe there is something under the car that was pinched, or catching--perhaps the e-brake cable is being pulled unevenly, as it shouldn't be pulling at all, but if there was anything changed out--I'm thinking you changed clutches, this could be a start?

 

Whatever it is, hope that you get it figured out, those whipples are awesome! and I know you can't wait to play!

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J R after your track event when you left the T/C on did you replace the Rotors? if so did you bleed the brakes? Didn't you replace the calipers?

 

Just a thought that you might have an issue with rotors or a caliper not releasing correctly.

 

Mick

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Ya, i don't know. i bled the rears last night and not one tiny bubble came out, so that wasn't it. Maybe it was the TC, but I wasn't on it THAT much. I have been planning on wiring up that TC "flip" though. Maybe time to do that. The brakes just don't feel smooth though. At lower speed it's not very noticable, but at freeway speed a medium braking sends some moderate vibration through the car. Might just have to take it someone here locally and try and get the lowdown. I hate taking my care to shops though... UGH.

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JR,

Dont recall in our discussions during buying your Brembo's if you said you did any upgrades to the rears. Your indication of having the correct retraction tool indicates you are still using the IPB (Integrated Parking Brake) caliper. My thoughts:

 

1) Listen while slowly turning rotor through the brake. Uniformity of force is desired. If you hear a hiss/drag sound, determine if you get the same sound 180 degrees through the rotation. If you do I would remove the rotor and look for dirt/debris between the rotor and axle flange. Small rust chunk will tilt the rotor and cause the drag.

 

2) If the drag is just for a certain amount of rotation it might of gattoen warped. Retain rotor to axle flange with washer and lug nut or use old open ended backwards snug but not fully torqued. Dial indicator readings over 0.015" in erratic condition would indicate a warp.

 

3) check in point where rotation is the eaiest to see if caliper will accept feeler gage between pad and rotor. You may have to do this at leading and trailing ends of the pad if you rotor has a lip at the OD (rotors do wear and make insertion from top hard. Ideal should be 0.008 - 0.015" If it is not retracting, there could be something in the aduster mechanism tohat is hung up. That is bad as they are hard to repair.

 

4) Check the parking brake cable and levers noted earlier on the caliper that nothing is binding.

 

5) If you have put on Eradispped +2 parts, there could be binding due to attaching bracket having a flaw or tightening got pins little biased to cause drag.. Best here is to retract pistons again and verify if when bolts are tight that assembly move smoothly on pins. Usual cause here is letting one wrench rest against the anchor bracket and rotating bolt to tighten. Wrench wedged against the anhor is a pry bar forcing pin side ways when torque is acheived.

 

Based on you think it is one side only, you could take that part off and do the above to see how the good one is before doing analysis on the bad side. It will be easier to see what is different.

 

DrKSGT

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JR,

Dont recall in our discussions during buying your Brembo's if you said you did any upgrades to the rears. Your indication of having the correct retraction tool indicates you are still using the IPB (Integrated Parking Brake) caliper. My thoughts:

 

1) Listen while slowly turning rotor through the brake. Uniformity of force is desired. If you hear a hiss/drag sound, determine if you get the same sound 180 degrees through the rotation. If you do I would remove the rotor and look for dirt/debris between the rotor and axle flange. Small rust chunk will tilt the rotor and cause the drag.

 

2) If the drag is just for a certain amount of rotation it might of gattoen warped. Retain rotor to axle flange with washer and lug nut or use old open ended backwards snug but not fully torqued. Dial indicator readings over 0.015" in erratic condition would indicate a warp.

 

3) check in point where rotation is the eaiest to see if caliper will accept feeler gage between pad and rotor. You may have to do this at leading and trailing ends of the pad if you rotor has a lip at the OD (rotors do wear and make insertion from top hard. Ideal should be 0.008 - 0.015" If it is not retracting, there could be something in the aduster mechanism tohat is hung up. That is bad as they are hard to repair.

 

4) Check the parking brake cable and levers noted earlier on the caliper that nothing is binding.

 

5) If you have put on Eradispped +2 parts, there could be binding due to attaching bracket having a flaw or tightening got pins little biased to cause drag.. Best here is to retract pistons again and verify if when bolts are tight that assembly move smoothly on pins. Usual cause here is letting one wrench rest against the anchor bracket and rotating bolt to tighten. Wrench wedged against the anhor is a pry bar forcing pin side ways when torque is acheived.

 

Based on you think it is one side only, you could take that part off and do the above to see how the good one is before doing analysis on the bad side. It will be easier to see what is different.

 

DrKSGT

 

 

Tom,

 

Thank you so much for the detailed "brakedown". I should have remembered you were a brake guru. It's really hard to tell what is going on, but I did drive it today and it seems that it's not as bad as I thought, but it still does make a decent vibration on medium to heavy braking. And I think I feel a "loping" when slowing stopping. Leads me to unfortunately believe that maybe I do have a warped rotor, which would be VERY disappointing as all 4 are brand new. But I will run through your list in the next couple days to do a thorough (at least as thorough as my ability) rundown of what is going on.

 

A couple quick questions though. When you say, :Dial indicator readings over 0.015" in erratic condition would indicate a warp.", what do you mean? I mean, what "dial"? Is this a tool I need to pick up? Well, I guess that's my only question for now, but thanks again!

 

BTW, got them Brembos installed yet?

 

Cheers, JR

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Tom,

 

Thank you so much for the detailed "brakedown". I should have remembered you were a brake guru. It's really hard to tell what is going on, but I did drive it today and it seems that it's not as bad as I thought, but it still does make a decent vibration on medium to heavy braking. And I think I feel a "loping" when slowing stopping. Leads me to unfortunately believe that maybe I do have a warped rotor, which would be VERY disappointing as all 4 are brand new. But I will run through your list in the next couple days to do a thorough (at least as thorough as my ability) rundown of what is going on.

 

A couple quick questions though. When you say, :Dial indicator readings over 0.015" in erratic condition would indicate a warp.", what do you mean? I mean, what "dial"? Is this a tool I need to pick up? Well, I guess that's my only question for now, but thanks again!

 

BTW, got them Brembos installed yet?

 

Cheers, JR

 

JR,

http://www1.mscdirect.com/eCommerce/NavigationServlet/Measuring-Inspecting/Dimensional-Measuring-Tools-Instruments/Drop-Test-Indicators-Holders-Accessories/Indicator-Holders-Accessories/Indicator-Base-Sets/_/N-1z13ocoZ77dbu?cm_re=Category-_-BodyLink-_-Indicator+%26+Base+Sets Should get you to place to see a Mitutoyo version - not cheap. Might you have a Technician friend to borrow from?

 

Loping you mention can be a thicknes variation in the rotor. We deal with in th 10 micron (0.0004") range new and getting over 25 can make a vehicle lope. Micrometer can check this easily - 10 readings at the OD of the rotor - each stud hole and in between each should be within 0.01". Does loping show up as pedal pulse to your foot, side to side twitch in steering wheel, or the seat of you pants? That can direct you more to front or rear and that it is thickness variation. Using parking brake at low speed and slow apply might manifest that it is rear and thickness as well.

 

No the Brembos are not on yet. Did a test last saturday at dealer and confirmed they fir my FR500 wheels. American took three shipments over a month to get me an entire vehicle set of TPMS parts. This Saturday should be the day.

 

Tom

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JR,

http://www1.mscdirect.com/eCommerce/NavigationServlet/Measuring-Inspecting/Dimensional-Measuring-Tools-Instruments/Drop-Test-Indicators-Holders-Accessories/Indicator-Holders-Accessories/Indicator-Base-Sets/_/N-1z13ocoZ77dbu?cm_re=Category-_-BodyLink-_-Indicator+%26+Base+Sets Should get you to place to see a Mitutoyo version - not cheap. Might you have a Technician friend to borrow from?

 

Loping you mention can be a thicknes variation in the rotor. We deal with in th 10 micron (0.0004") range new and getting over 25 can make a vehicle lope. Micrometer can check this easily - 10 readings at the OD of the rotor - each stud hole and in between each should be within 0.01". Does loping show up as pedal pulse to your foot, side to side twitch in steering wheel, or the seat of you pants? That can direct you more to front or rear and that it is thickness variation. Using parking brake at low speed and slow apply might manifest that it is rear and thickness as well.

 

No the Brembos are not on yet. Did a test last saturday at dealer and confirmed they fir my FR500 wheels. American took three shipments over a month to get me an entire vehicle set of TPMS parts. This Saturday should be the day.

 

Tom

 

 

Yikes, ya, I'll probably avoid purchasing that piece of equipment, but hopefully it can he troubleshot in the meantime. To answer your question, yes, I notice the "loping" in the pedal, but only barely and only at low speed when lightly coming to a stop. And I DEFINITELY notice a twitch in the steering wheel when braking.... mostly at +30mph. Man I wish I knew what was going on. The car is so powerful now and I just want to put it through the paces, but these brakes have me concerned. How frustrating to upgrade something and have it be worse off then the OEM you took off. I don't get it.

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That happened to my wifes car. Turned out the caliper slide pins were dirty and hanging up. I cleaned and lubed the pins. Problem solved.

 

 

Hoping this is the case here, but who knows. On that note, pardon my ignorance, but i've never had a caliper APART other than to install pads... when you say slide pins, are these the inside part of the cylinder? I just don't know what your talking about when you say slide pins? Can anyone give me a quick tutorial on how to clean and lube these up?

 

Thanks, JR

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I have not torn into the mustang brakes yet. On my wifes dodge, the caliper halves are held together with two threaded pins that let the caliper halves slide relative to each other. It only has pistons on one half the caliper, so the other half must slide when the brakes are released.

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Yikes, ya, I'll probably avoid purchasing that piece of equipment, but hopefully it can he troubleshot in the meantime. To answer your question, yes, I notice the "loping" in the pedal, but only barely and only at low speed when lightly coming to a stop. And I DEFINITELY notice a twitch in the steering wheel when braking.... mostly at +30mph. Man I wish I knew what was going on. The car is so powerful now and I just want to put it through the paces, but these brakes have me concerned. How frustrating to upgrade something and have it be worse off then the OEM you took off. I don't get it.

 

JR,

Front would only need to make sure surfaces between the rotor and the bearing are clean and free of burrs. These Shelby Rootrs should be good. The idea of the slide pins does not apply here caliper is fixed (bolts hold housing direct to the front knuckle). Because pistons are on both sides housing does not move, just the pistons extend to force pads into the rotor.

 

Rear Calipers using the Eradispeed brackets have the pins and boots that can get contaminated. When you have done pad changes have you taken the two bolts that go through the ears on the housing that holds the piston off completely . The part the bolt attached to is what supports the caliper and allows entire housing to slide back and forth over the rotor. These pins are usually buried in the anchor attached to the axle and have a boot greased on inside. Function is to keep debris and water from hindering free side to side motion of the caliper over the rotor. Not having seen the Eradisppeed brackets, I do not know if you had to put them together. PINS BEING TILTED SLIGHTLY WILL CAUSE CALIPER BIND AND DRAG.

 

Suggestion is to unbolt one end of the caliper and rotate it up away from the rotor (brake hose permitting) to take pads out. Do not apply brake during this eval as I would like that you do not need to use the piston retraction tool. With pads out, secure the boly again. Now you should be able to slide the cliper back and forth. Check that it moves freely back and forth over the rotor. Apply force between the bolt so it moves like piston would move during apply. Also suggest staring with one that seemed hot when you started this thread. Correction if binding is to loosen attaching bolts about half a turn and see if it loosens up. The pins usually have a hex shape to keep it from spinning when mounting bolt is torqued. Torquing operation needs to be between bolt and pin so they are tighten to the caliper ear. Any load put into the surrounding parts can distort the joint and make the pin bind.

 

Wish I could talk you through this but I have stuff to get ready for trip tomorrow. Back Saturday and available to talk after 11:00 my time. Hope you still ahve my number.

 

Tom

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Todd and Tom,

 

Thank you VERY much. For some reason when I was thinking something was awry with the mechanics of the calipers, I just assumed the piston, but never even considered it could be the slide pins. Whatever is happening seems to be a "subtle" problem... not drastic, which makes it even more difficult to ascertain. But sometime one of these next couple nights I'll do exactly as Tom said and try and see if each slide pins is operating correctly. Speaking of which, does anyone know the proper torque spec for the slide pins bolts? Maybe I've over torqued them and have caused them to bind up.

 

Thanks again guys. I hope this is isolated soon. I'd really like to just go cruise this car now, but it just stressed me out to drive it at the moment.

Edited by 07SGT5687
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I had mine bind up at the track once a couple years ago. It was ignorance on my part, but there are two things that I didn't do that I should have and I'm not sure which one caused my problem.

 

1) I was swapping to used track pads from relatively new street pads, so skipped turning in the piston that day because I had plenty of room to fit the used Hawk pads in there.

 

2) Forgot to line up the key slots perpendicular to the caliper to properly align with the key on the back side of the pad resulting in uneven pad wear.

 

Since then I've been paranoid about meticulously checking these two things every time I do a rear pad swap.....just did it on the Boss last Saturday prepping for this weekend's event. Here's a great writeup 6-speed did a couple years ago: http://www.teamshelby.com/forums/index.php?showtopic=51062

 

I use the Harbor Freight piston tool shown in this writeup and it works very well. Cheap too at $20 plus shipping.

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For some reason when I was thinking something was awry with the mechanics of the calipers, I just assumed the piston, but never even considered it could be the slide pins.

 

 

Did you index the notches in the caliper pistons to 6 and 12 o'clock?

 

That is a VERY important step as it keeps the piston from rotating while applying the parking brake.

 

There is a nub on the back side of the brake pad along the outside edge that engages the notch in the piston which in turn keeps it from rotating. If you didn't index the notches at 6 & 12 o'clock the nub will be contacting the edge of the piston and cause the piston to "cock" in the caliper bore which could easily lead to brake bind.

 

Ya might wanna check that, just in case. And it's only on the rear disc brakes that have intergal parking brake mechanisims built into them.

 

 

HTH,

Phill Pollard

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Here's a great writeup 6-speed did a couple years ago: http://www.teamshelby.com/forums/index.php?showtopic=51062

 

I use the Harbor Freight piston tool shown in this writeup and it works very well. Cheap too at $20 plus shipping.

 

That is a great write up... and exactly how I've done my installs. Although before recently it was without that wonderful caliper tool which I ALSO got from Harbor Freight, but the price is now $45.

 

Did you index the notches in the caliper pistons to 6 and 12 o'clock?

 

That is a VERY important step as it keeps the piston from rotating while applying the parking brake.

 

There is a nub on the back side of the brake pad along the outside edge that engages the notch in the piston which in turn keeps it from rotating. If you didn't index the notches at 6 & 12 o'clock the nub will be contacting the edge of the piston and cause the piston to "cock" in the caliper bore which could easily lead to brake bind.

 

Ya might wanna check that, just in case. And it's only on the rear disc brakes that have intergal parking brake mechanisims built into them.

 

Yes, I always align the knotches and pin.

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Anyone know exactly what kind of lubricant I should use on the caliper slide pins?

 

If you refer the shop manual link that you referred to a few posts back you'll see under Materials:

 

Silicone Brake Caliper Grease and Dielectric Compound XG-3-A; specification ESE-M1C171-A.

 

You can buy this grease at any Ford parts department.

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If you refer the shop manual link that you referred to a few posts back you'll see under Materials:

 

Silicone Brake Caliper Grease and Dielectric Compound XG-3-A; specification ESE-M1C171-A.

 

You can buy this grease at any Ford parts department.

 

 

Once again, I need to reference those shop manuals MUCH MORE often! Thanks again 6 speed.

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Get this... I get fed up last night and drive over to Phil Long Ford. I explain to one of the service guys what I'm experiencing and ask (foolishly) if they think they can take a look at it.

 

:hysterical:

 

He says.. "Um... well, we could take it back to stock for you and then make it work right again, but that's about it." :doh:

 

What a joke.

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Get this... I get fed up last night and drive over to Phil Long Ford. I explain to one of the service guys what I'm experiencing and ask (foolishly) if they think they can take a look at it.

 

:hysterical:

 

He says.. "Um... well, we could take it back to stock for you and then make it work right again, but that's about it." :doh:

 

What a joke.

 

 

Can you get to Phil Long in Motor City/Co.Springs?

 

They are a SVT & Shelby certified shop with a SVT certified tech on staff.

 

I took mine in day before yesterday and one of the Service advisiors saw my front Shelby Baers through the KR wheel spokes and told me he already knew he'd see some special sfuff under the hood...oh, and he knew the KR rims right off the bat.

 

They *know* Shelby's at Phil Long Motor City Ford (Sales AND Service). I'm not sure about any of the other Phil Long shops though.

 

They also have a Shelby GT350 sitting on the showroom floor and they tell me it is ONE OF ONE that has a Dealership name in the "This car was specialy built for Phil Long Ford" line on the window tag. The SVT Sales Mgr. handed me the keys and said "get in and start it up".....DAMN it sounds sweet!

 

 

Phill Pollard

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Can you get to Phil Long in Motor City/Co.Springs?

 

They are a SVT & Shelby certified shop with a SVT certified tech on staff.

 

I took mine in day before yesterday and one of the Service advisiors saw my front Shelby Baers through the KR wheel spokes and told me he already knew he'd see some special sfuff under the hood...oh, and he knew the KR rims right off the bat.

 

They *know* Shelby's at Phil Long Motor City Ford (Sales AND Service). I'm not sure about any of the other Phil Long shops though.

 

They also have a Shelby GT350 sitting on the showroom floor and they tell me it is ONE OF ONE that has a Dealership name in the "This car was specialy built for Phil Long Ford" line on the window tag. The SVT Sales Mgr. handed me the keys and said "get in and start it up".....DAMN it sounds sweet!

 

 

Phill Pollard

 

 

Thanks for the recommendation. I called them and I'm not sure if i'm going to go that avenue quite yet. They gave me a bit of a tentative... "Ya, I suppose we could look at it." Not quite the level of confidence I'm looking for, considering I'd be taking it all the way to the Springs. But I'll keep it in mind if my options run out locally. Just called O'Meara Ford (sorry Steve-O... I need Matt to look at it... someone I can trust), who does most of the conversions in the area and they are a Roush dealership so I know they have some experience with aftermarket brakes. I need to get this crap figured out so I can enjoy this car before the season is half over with. Almost judging by the snow today, the season hasn't even started yet!

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