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Stop here! Let's talk about brakes

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  • ecotrklvrecotrklvr Member Posts: 519
    Alcan has a great idea there. I bought one of these "non-contact" infrared thermometers at Radio Shack last year for about $30. Very handy - you get a very accurate reading almost instantly; less that a second for sure. You can tell where it's aimed by using the LED beam as an aiming tool. For a brake rotor, maybe you can find a gap in the wheel that lets you see th rotor. If not, you'd have to get under the tuck to be able to "see" the inner side of the rotor.

    For this brake issue, I'd alter his recommendations slightly. Before the hard stops, just drive for a bit - maybe 3 miles or more. Then beam the LED aimer at the brake rotors. (You can be several inches away - makes no difference to the reading.) This will tell if you have a dragging brake (stuck caliper) on one side of the truck. Then do the several stops thing, and beam them again.
  • bpeeblesbpeebles Member Posts: 4,085
    My goodness, there is no need for all the technology to check for dragging brakes.

    1)Drive at highway speeds for a few minutes
    2) pull into a "rest area" and use the EMERGANCY BRAKE to come to a stop. (do not use brake pedal)
    3) Gingerly feel the LUG NUTS of the 2 front wheels. The presense of any heat on the lug nuts indicates dragging brakes on that side.

    ALTERNATIVE: jack up each front wheel and spin it by hand. If it is not easy to spin the wheel -- the brake is sticking on that side.

    Lets not forget that the original poster has already declared that the caliper is not sticking. We have to assume they know what they are talking about when they make that statement.

    In any case , following my step-by-step process above will GUARANTEE a sucessful diagnosis of this "pulling" problem.
  • ecotrklvrecotrklvr Member Posts: 519
    OK, you got me - I'm a tech nut. You save thirty dollars - and I get another toy. Either method will work - for the thing he doesn't have - no dragging brakes, we are told. It's nice to be able to do either method, without having to jack the truck up.

    He should still do the multi-stop thing that Alcan suggested, and compare the two sides. Here, the thermometer is nicer as you don't have to judge between 100' and 150' with your hand.
  • wtd44wtd44 Member Posts: 1,208
    Right on! The temperature difference the hand can positively identify is not nearly as subtle as the ability of the thermometer.
  • clueless3clueless3 Member Posts: 3
    2002 A6 has developed pulsating brakes, especially at low speeds (arriving at stop). Dealer check finds no problem with brakes; sm thinks problem is caused by uneven tire wear. I can't envision why that would be the cause. Any comments. Tires have 37,000 and have been rotated.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    hi clueless,

    Please try not to do duplicate posts. We'll answer your question in the Maintenance Costs forum where you also posted.

    thanks

    Host
  • prphzprphz Member Posts: 2
    Hello All,
    I have a 92 Lesabre & the ABS light is on. I have a GM code reader that decodes Treves II , Bosch 2s &2u. My car uses Treves IV abs. Can i still use the code reader? (code reader manual says "for GM 82 to 95 cars", but does not list Treves IV ) It reads the ECM codes fine. But when i try abs the light blinks off then stays on, and thats it. The ABS light came on after a hard & fast stop, and has not turned off. Any help would be great.

    Thanks,
    Eric
  • alcanalcan Member Posts: 2,550
    You'll need access to an ABS capable scanner such as the Snap-on MT2500.
  • prphzprphz Member Posts: 2
    The scanner I have does read ABS and ECM.
    Is Teves II ABS different from Teves IV ABS, in code scanning?
  • chuck46chuck46 Member Posts: 6
    I have replaces the flex hose and the caliper, brake will bind while I am driving, If I release the pressure by the bleeder , brake releases and I can go untill it binds again. It is just the left-front drivers side brake. any suggestions?
  • alcanalcan Member Posts: 2,550
    Try this diagnostic routine: unbolt the master cylinder from the booster (leave the lines attached), pull it forward off the mounting studs far enough to slip a flat washer over each stud to act as temporary spacers, then re-install the master. If the symptom goes away, the booster push rod is out of adjustment. BTW, the pedal will be lower with the washers installed.
  • vw148vw148 Member Posts: 2
    Hey I was just wondering if any one has ever had this problem and if any one had any advice. I have just replaces all of the lines, calipers and the master cylinder twice of my 1989 VW Jetta. The guys at the shop have been working on it for about 3 weeks and they still can't get a decent pedal out of it. Any one have any ideas?? :confuse:
  • bpeeblesbpeebles Member Posts: 4,085
    If I recall my daughters old 1989 Golf, I did all my own brake-work on that and it had no special nor unique 'gotchas'. It sure sounds as if there is still air in the system somwhere.

    If there are no external leaks beyond the master cylinder, then the lines and brake-components at the wheels can be ruled out as the problem. That means your problem is either an internal leak of the master cylinder or air in the system.

    The above is assuming that there is no "squishiness" of the pads and the rear drums are assembled and adjusted properly.

    VW uses a spring-loaded wedge as the automatic-adjuster in the rear. (rather than a starwheel) This means the the EMERGANCY BRAKE must be applied to adjust the rear drums. (unlike braking in reverse for a starwheel design)

    Was it pressure-bled -or- vacuum-bled after all the work was completed?
    Have you considerd that the brake-booster may be the problem?

    Another "test" to perform is the see if the brake pedal will "pump up" with successive pedaling. If it does "pump up" and become a solid brake-pedal, that is a sure sign of the rear drums being mis-adjusted. (The shoes are so far away from the drums, that it takes several pumps to make them contact the drums)

    Somtimes, hard braking on a dirt road while somone is observing the wheels can help isolate which wheels are not receiving the braking forces. Keep in mind that VW uses an "X" plumbing pattern for the brakes.

    Also, when it comes to replacing parts on any machine, it goes without saying that "New does not mean good" I have often seen new parts that are bad right out of the box.
  • vw148vw148 Member Posts: 2
    Thanks for your help. The people working on my car seem to think that the system has a huge air bubble in it and they can't get it out with normal bleeding so they need to try vacuum bleeding. Thanks again.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    All modern well-equipped shops "power-bleed". If they are doing it "by hand" that's pretty lame these days.
  • ecotrklvrecotrklvr Member Posts: 519
    I wonder what percentage of shops that work on Readers' vehicles truly qualify as "modern". Not that they shouldn't, but I live in a big city - but millions don't, and don't have quick access to truly modern shops.

    I shudder to think of Stan and Ollie (or their grandkids) bleeding my brakes.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    I haven't seen a shop manually bleed brakes in....gosh...5 years or more. It's really primitive, time consuming and messes up your car---as this case proves.

    Unacceptable way to work on a safety-related item on a modern car! A shop shouldn't be allowed to do brakes like that IMO. We're talking lives here, and one air bubble can do a lot of damage. This is a nearly new Jetta, not a Model A Ford.

    I'd take my business elsewhere.
  • bpeeblesbpeebles Member Posts: 4,085
    I have not bled brakes using the brake pedal for at least 20 years. I have been using a vacuum-bleeder at home for over 20 years. (I built it from a hand-pumped breast pump once my wife no longer needed it for the children)

    I use it not only for bleeding brakes, but also for bleeding hydrolic clutch systems and for sucking fluids out of things. (such as sucking the power-steering fluid out of the resivour) It can also be used to suck the oil out of a gearcase such as xfercase or differential.

    Do not forget that ABS systems also need "special attention" when bleeding them. There is often extra bleeder nipples in the system and somtimes a small lever to push so the ABS system gets properly bled. Just bleeding the wheel nipples will not do it.

    My VWs actually "share" the brake fluid with the clutch fluid. That adds some more "special attention" to the mix.
  • wtd44wtd44 Member Posts: 1,208
    All pumps not being the same, you can find the real thing at this site:
    Kit 06820 looks real strong. I got mine from J.C.Whitney many years ago.

    http://www.mityvac.com/kits.html
  • alcanalcan Member Posts: 2,550
    This is the bleeder I use for simple, one man operation. Might be overkill for a DIY, but works great:

    http://www.speedibleed.ca/
  • chuck46chuck46 Member Posts: 6
    TY alcan, I did that and it was a problem, replaced master cylinder and now it is working fine ty again
  • ecotrklvrecotrklvr Member Posts: 519
    Alcan -

    Brilliant! Never heard of that trick. You rescued a really rare car, too - the Geo Metro Convertible is sorely missed here in So Cal.
  • bpeeblesbpeebles Member Posts: 4,085
    The ( http://www.mityvac.com/kits.html ) is a VACUUM bleeder while the ( http://www.speedibleed.ca/ ) is a PRESSURE bleeder.

    Beware that each type has its own plusses and minuses. Some vehicles actually SPECIFY which type to use.
  • alcanalcan Member Posts: 2,550
    brake binding by chuck46

    Re: left front brake binding on 91 geo metro conv. [alcan] by ecotrklvr
  • bigbutrbigbutr Member Posts: 111
    I own a 1996 Chevy S10 extended cab with the 4.3 V6 with just under 68000 miles on it that I currently use on a rural post office mail route. I will soon be replacing the brakes and wondered if I would get any benefit by switching out the original rotors to a drilled, slotted or drilled/slotted combination set instead of just turning the ones already on there. I have read where they decrease stopping distance, dissipate heat better, yada, yada, yada, but I want to make sure before I invest the money. Is one style better than another, or would a the combination drilled/slotted pair be the best?
    I only use the truck right now for the mail route a couple days a week plus light driving around town (I don't have a Sirius adapter for my other car yet, so I find a reason to drive it).
    Thanks for any responses.

    Steve
    Dothan, Alabama
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    I don't think drilled or slotted rotors would be of any use whatsoever to you in the type of driving you are doing. You'd be better off getting a top quality pad and good quality aftermarket rotors. I'm not a big fan of turning OEM rotors but if money is an issue, then at least get really high quality aftermarket pads. It's the pads that will give you better braking, not the visually interesting but (at normal speeds) rather useless slotted or drilled rotors.
  • wtd44wtd44 Member Posts: 1,208
    So, there really is a valid reason other than eye appeal for the holes and slots. It surely sounds feasible. Where do you currently stand on lathe turning grooved rotors versus replacing them when doing brake renewal work? Are the days of resurfacing rotors coming to an end?
  • alcanalcan Member Posts: 2,550
    Depending on the cost of replacements, machining might be viable if the rotors won't end up close to discard spec and there are no visible cracks in them. That's been a problem with drilled rotors, whereas slotted ones tend to be structurally stronger. The problem with slotted rotors is that the slots become shallower after machining, reducing their effectiveness. Given a choice, I'd like to replace either type rather than cutting them.
  • bigbutrbigbutr Member Posts: 111
    I thought there might be a structural dilemma with drilled rotors, giving you are weakening the overall rotors by cutting holes in them. I am pretty quick at delivering the mail, but it is a rare situation that I get up to highway speeds. I thought they might be more eye-candy than anything else for my type of driving and I appreciate the feedback. Anyone have any places they can recommend that sells quality aftermarket rotors and pads. I try to stay away from the chain autoparts stores if at all possible. Thanks again.
  • waiwai Member Posts: 325
    I just bought a VR6 Jetta and have 1,200 miles on it. I noticed everything is OK except the braking power is not sufficient for high speed braking. ( rear disc is too small for a 17" inches wheel.) Any suggestion to improve the brake.
  • ruking1ruking1 Member Posts: 19,826
    The simplest is to go to a more aggressive brake pad (Hawk, Ferodo, Porterfield come to mind) and be ready to change pads and rotors out on a more frequent intervals.

    Here is a site to get you started.

    http://www.bmwmarketplace.com/v3beta/bmw/tips/general/brakepads.cfm

    For more radical improvements, bigger brake pad and rotor kits are probably in order. You of course know that you may/may not want or have to change tires and rim combinations to allow for whatever bigger pad and rotor combination you select. Then you will probably find you do not like the stock strut and shock combinations and want to add upper and lower strut bars and rear upper shock bars.and rear sway bar :(:) You probably are already aware that a bigger wheel/ tire and bigger pad and rotor combination, while increasing stopping performance, will in fact impede other performance parameters.
  • marsha7marsha7 Member Posts: 3,703
    Obviously resurfacing rotors has opinions on both sides, so here is mine...the carmakers, in order to save weight, appear to design the current rotors without much extra "meat", unlike 20 years ago when they added an extra 1/8" so they could be cut once, maybe twice, if not too badly grooved or warped...to get every last tenth of mpg, they now shave weight anywhere they can, and extra thickness on a rotor is sheer dead weight of cast iron...if the rotors are not warped, and if they are ventilated, you MIGHT get away with one resurfacing, but be sure to use a micrometer to check thickness to be sure it is safe...I believe that solid, unventilated rotors should be immediately replaced, unless they are just glazed, not warped, and can be re-used with some emery paper removing the glaze...the simple fact is that if you keep any new car, made after 2000, 100K miles or more, you will certainly install more new rotors than a car from 20 years ago kept for the same mileage...of course, a car from 20 years ago might be lucky to last 50K miles prior to disintegration, so new rotors might never be a problem...:):):)ymmv
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Another issue is that by making the rotor thinner you are in effect decreasing its heat-sloughing properties and possibly subjecting it to more frequent warping.

    For instance, if you are running turned rotors and you run into a specifically bad situation (rare but possible) of say running down a long hill and then hitting some standing water, that is likely to warp a hot rotor.
  • marsha7marsha7 Member Posts: 3,703
    I believe you and I will agree that if you look at a rotor head-on, meaning that you are looking at it and seieng the entire round disc, if you can see thru the metal and see light thru the disc, we both believe that it is beyond turning or sanding, and just might need a new one, eh???...:):):):):)
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    scoff if you will, but I think everyone on the board will agree that warped rotor complaints are way up and this suggests OEM metallurgy of rotors at the quality level of a frozen TV dinner tray.
  • wtd44wtd44 Member Posts: 1,208
    So... what would be a good choice of aftermarket rotor for my daughter's 2004 Grand Cherokee Jeep? Please be specific, and hey, everyone speak up! :shades:
  • ruking1ruking1 Member Posts: 19,826
    A quick and dirty would be the Napa brand (for your application). Of course you'd have to shop it a bit to see if it indeed meets the bang for the buck criteria.
  • wtd44wtd44 Member Posts: 1,208
    Hey! Fast and effective as the two of you are, I say thank you very much! Those are both great leads that I WILL pursue. I have heard just enough about Grand Cherokee rotors to now assume the real solution is to replace them. My daughter missed the 12 month window of opportunity to get warranty consideration, so at some 17K miles, it will be on us. Great warranty, no?
  • ruking1ruking1 Member Posts: 19,826
    Yeah the Napa brand was mentioned on the Corvette web sites. There are a lot of guys who do weekend racing and it is almost nothing for them to replace super aggressive pads between heats and certainly rotors when warranted. Abuse might be considered an easy day. They seem to hold up well in those kind of conditions.

    I have priced the GM oem rotor replacements and a cursory call to the local Napa Parts store indicated a far cheaper price.

    I am also impressed with the Brembo line per se. However for the VW Jetta TDI application in the Brembo replacement line, there seems to be a higher rate of warped Brembo replacement rotors. Two of the folks that registered these findings I happen to know personally, so there is some question in my mind.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Winning friends all over the world with policies like that, yessir!

    Brakes and tires are where all the money should go, because without those, the rest doesn't matter.

    To be fair, when assessing rotor warpage and reasons therein, one has to look at the vehicle itself (weight, power, and size of rotor spec'd by factory) and also people's driving habits.

    I was just following a big fat SUV the other day down the mountain, and that brake light was on for I swear 2.5 miles without a let up. Now really, what chance do those rotors have (or the pads) for long life? I bet if it was night time I could have seen them glowing red.
  • ruking1ruking1 Member Posts: 19,826
    Be glad you were BEHIND him! :(:)
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    I know...I can just hear the accident report:

    "the brakes were defective..I pressed and pressed and nothing happened. It's not my fault. This car is dangerous!"
  • marsha7marsha7 Member Posts: 3,703
    as I thought they only made brakes for hi-perf cars, but they also make hi-perf brakes for ordinary cars like my 04 Crown Vic and my 04 Ram 1500...after perusing their web site, one question remains...which would you buy, the rotors with drilled holes, or the rotors with slots in them???...I had never seen slotted rotors until the website, I had only seen photos of the drilled ones in car mags, usually with a red or yellow caliper, just to make it stand out...which one would you buy for hi-perf and heat dissipation?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Oh I think slotted are better overall. One problem with drilled rotors is that you are possibly compromising the structure of the rotor (weakening it)

    image

    ---another is that road dirt can clog the drilled rotors rendering them no better than ordinary rotors.

    Also how the rotor is ground is important as is the metallurgy. It's quite a science and not all aftermarket rotors are equal.

    Little Known Fact: did you know that if you increase your tire size 1" you increase your braking distance as much as 10 feet?

    So probably a lot of street racers out there have totally negated their fancy brake upgrades by using larger tires!
  • sequoiasoonsequoiasoon Member Posts: 223
    Check out this site http://www.raceshopper.com/about_us.shtml they have a lot of great info in the FAQ's about rotors and pads. They also carry rotors from SP performance which are getting very good reviews from the weekend racers. Here is some info on the cross drilling http://www.sp-performance.com/hole.htm. You can also look at cryo-treated http://www.frozenrotors.com/ (funny Jeep GC is the top seller). One of the biggest things though is too make sure you properly bed the new rotors and pads. Raceshopper has a good write up on it. They also don't recommend Ceramics as they retain too much heat and contribute to warping. I went to Pep Boys to get pads with my brother -in-law and the parts guy there said the same thing. They were having a lot of warranty/return issues with the service dept. when they were using the Ceramics. At least for now they are recommending semi metallic again.
  • wtd44wtd44 Member Posts: 1,208
    Hmmmmmmm! The problems stay the same, but the answers keep changing... That indicates there aren't any good answers. :(
  • ruking1ruking1 Member Posts: 19,826
    I would also agree! In a manner of speaking there is no free lunch with brake rotors and pads. What comes out in oem cars is certainly a balance of a huge number of factors. From a consumers point of view, I try to study if the particular vehicle I have selected has the bean counter affliction, and if it is bad enough bypass the model all together or look to specific aftermarket solutions.

    Of the current brake pad product line, depending again on ones goals, the aftermarket has developed sort of a loose code, which they refer to as "rotor" friendly all the way up to "full aggressive" race pads that operate well at up to XXXX temperatures. (i.e. verboten:CAN TRASH ROTORS ALIVE at one sitting)
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    My understanding is kind of simple-minded:

    If you want to stop real fast, reliably, time and time again without fade, you are going to eat rotors for breakfast.

    If you want quiet brakes, nice soft cushy feel when cold, a velvet pedal that you don't have to push real hard---you aren't going to stop real fast, reliably, time and time again at high speeds, but you'll get longer rotor life.

    Take your pick, I say, or, like many of us here, we go somewhere in between.

    On my car (Porsche 928), I plan on ditching the rotors at each pad change. I don't always have to, but I plan on it. That's the price I have to pay for what I want, as do most porsche owners. If you complain because your Corvette or Boxster doesn't get long rotor life, then you haven't fully understood what the engineers of your car intended.

    Sometimes, however, it wasn't the engineers, but the bean-counters who intended to save $5 a car and give you rotors for "average use and high comfort".
  • wlbrown9wlbrown9 Member Posts: 867
    I replaced the rotors on the '00 GCL with basic ones from Autozone for about $100/pair. This was at about 15,000. They were still good when we traded May '04 at about 65,000-68,000 miles. They survived a high heat event when one of the front calipers stuck and heated up enough to warp the rotor. Wife called me so I went and traded vehicles with her. Real hot and a warp wobble. Once they cooled down, I lubed the slide pins on the Caliper and the rotors went back to normal...unlike the factory rotors that warped with very little high heat. You don't really have to go to special, high performance rotors to cure the problem. It took maybe an hour for me to change them myself...a lot of that time to figure out how tight the caliper bolts were on from the factory.

    Enjoying the beauty of not owning a Jeep after having 2 of them for a 5 year period. GMC Envoy is not the greatest vehicle in the world, but IMHO much better than the Jeep. These new vehicles are convincing me that a factory backed extended warranty at a reasonable price may be just part of the cost of ownership.

    Bill
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