posted by
someone claiming to be Rich G.
on
Mon Jul 22 09:17 CST 2002 [ RELATED]
|
|
Hi,
The rear rotors/pads on my wife`s 855 were replaced a month ago & last week I noticed the familiar judder from the rear when applying the brakes at 55/60 mph. We took the car into the dealer this am & just got a call that the rear discs need to be replaced. Understandably, I was not too happy to hear that news & less so when it was suggested that maybe the emergency brake had been left on. Neither my wife nor I use the e. brake unless we park on a hill which is almost never.
I am very reluctant to take the hit for another set of discs since I see no reason that the first set should be warped& I could find myself replacing a new set in another month. I should point out that there has been absolutely no high speed braking, just normal driving.
What gives here?
Thanks,
Rich
|
|
-
|
|
|
Rich:
Aside from the torque stick arguement, I have solved the rotor problem on all of my Volvos, 740, 854 turbo, & R wagon. Because of the elimination of asbestos metal additives are now used in the brake pads, sometimes the pads glaze from high heat and end up chewing into the rotors which can make the rotor overheat & warp. This is why Midas & such offer lifetime guarantees on pads, but not the rotors..guess what wears out first? When I first bought the 854, the dealer would replace the rotors under warranty...many times. Volvo surely knows about the problem. When I moved to Reno, I found an independant Sweedish mechanic and he solved the problem by using a softer pad. He claims it is a Volvo pad, but I do not know for sure. Try a softer pad, it certainly solved my problem.
Wills
|
|
-
|
|
|
I say pay for it one more time, under one condition. That a torque stick shall never touch your lugs EVER AGAIN! That a calibrated torque wrench be used on a cleaned or clean mating surface of the hat of the rotor, with a proper tightening sequence. And that should you ever catch a tech using a torque stick on your lugs, that a new set of rotors be provided free of charge.
Techs no better than to use said torque sticks on my car now. If a service advisor or tech is unwilling to comply with this request, declare that you will no longer have your car serviced there, and that you will spread your poor experience with their dealership to everyone and anyone, regardless of whether they own or a Volvo, or will ever consider owning one. And lastly, that you will lodge a complaint with the manager, owner, of the dealership, as well as VCNA.
|
|
-
|
|
|
Wait a second.
Isn't a "torque stick" simply a fixed-torque, click-style, torque wrench?
Except for the fact that it might occassionally need calibration (is that the issue? . . . ALL torque wrenches need occassional calibration), what could be better?
Okay, click-style torque wrenches are not as precise as beam-, or dial-, style torque wrenches but, in my opinion, that is only in laboratory situations. In other words, in a laboratory, they are able to mount the torque wrench in a jig and use it so that they can precisely see that the needle is pointing to a particular measurement and then compair the actual torque with that measurement. They do the same with a click-type torque wrench and the beam-, or dial-, style wrench always comes our more accurate.
But in the real world, a click-type torque wrench is more accurate. Most of the time when you are using a beam-, or dial-, type torque wrench, you cannot easily view the gauge area while, at the same time, actuating the wrench. The result is an inaccurate torquing which is much more inaccurate that the implied inaccuracy of a click-style torque wrench.
BTW--why this incredible sensativity to lug torque for Volvo's. Most FWD cars have some sensativity to lug torque, but the 850 appears to have an extreme sensativity. Is this a poor design issue?
PS--I just did the brakes on my wife's 850, about a month ago, and the rotors are now warped. And I was painstaking about the lug torques.
|
|
-
posted by
someone claiming to be nexus
on
Tue Jul 23 13:13 CST 2002 [ RELATED]
|
|
I agree with Sin, season the rotors. Also about torque wrenches. They are all very inaccurate. Temp, lube, moisture in the air all effect torque values. The rotors do not need to be at x lb/ft so much as all at the same value. Back to my apathy stance.....Whatever makes you happy :)
|
|
-
|
|
|
No, a torque stick is kinda like a socket with an extension, except it is only one piece, and supposedly reduces a high predetermined impact torque application to a lower preset torque.
Because it relies on a consistent torque to produce a consistent torquing, and the setup of air pressure in most shops, this is impossible. Furthermore, because it uses impact, and momentum, overtorquing is a real concern.
As for your warping, did you make sure the mating surface was clean? Often rust accumulates on the rotor or rim. Also, there are some things to do to prevent warping, such as keeping the car rolling after a heavy stop to allow for even cooling, not applying the parking brake when the brakes are still hot, etc.
|
|
-
posted by
someone claiming to be Frank
on
Tue Jul 23 00:59 CST 2002 [ RELATED]
|
|
Sorry but I don't agree with your opinion of torque sticks. Volvo sent them to all Volvo dealers as required special tools and we use them daily, have since the day Volvo sent us the first one (maybe 10 yrs ago now?) AND we have NEVER once had a problem with them. We've never warped one rotor or had a wheel loosen up and I use them on my cars too.
They're STILL a required Volvo special tool so if they're NG, why does Volvo send them to ALL Volvo dealerships and request that we use them for ALL of their cars? Before torque sticks came out, we use to hand torque all Volvo lugnuts but that's no longer necessary.
I've also been a tech for 24 yrs now (for a living) so I think I have a little experience with this stuff too.
Being that I work for a large successfull Volvo dealership and have for many years, I'd appreciate that you not say things to people here that contradicts what VCNA has us doing for a living as those in the business don't need to deal with customers who take some of this literally.
|
|
-
|
|
|
If this is so, then why do all the mechanics in my shop agree that they are often highly inaccurate, and refuse to use them on their own cars? At the dealership I go to, many techs are the ones that are the first to say that these torque sticks are inaccurate. If you have never had a problem with them, you are either unbelievably lucky, or your customers haven't realised that some of their problems are due to this inaccurate tool.
VCNA is not the be all and end all or proper car maintenance. As any business, they must compromise here and there. It just so happens that VCNA considers this an acceptable risk.
Just think about the way this tool functions. By using an impact gun, running off a central system, the torque the impact gun provides, varies so greatly. Say a shop has 10 bays, each bay having one outlet for air tools, all running off one large compressor. You're telling me that each impact gun is going to receive the same amount of pressure when it is the only drain, compared to when all 10 bays are using pressure?
If you are happy using this on your car, and your customers, that's fine. But with them paying your dealership for service, they have the right to request the added accuracy of using a proper torque wrench. And yes, your dealership has the right to refuse, but then again, trust me, most Volvo dealerships, atleast in my area, have no problem whatsoever with this issue.
|
|
-
posted by
someone claiming to be Frank
on
Tue Jul 23 13:28 CST 2002 [ RELATED]
|
|
It's not VCNA (an American company), it's Volvo (the Swedish guys who build the cars, write the manuals) who sent us these tools and shows them in their OEM Volvo service manuals. Being that they built the cars and wrote the manuals, I'd trust what they say and have for the now 18 yrs I've been a Volvo tech (more years working on other types of cars).
As for a customer requesting hand torquing, sure why not?
|
|
-
|
|
|
Torque sticks are ok for somethings and not for others. Thats the bottom line. Should an axle be hand torqued? How about the head? From a racing standpoint, everything gets hand torques with the exception of the wheels. This does cause problems at time though.
|
|
-
posted by
someone claiming to be Frank
on
Tue Jul 23 04:25 CST 2002 [ RELATED]
|
|
The point I made is regarding lug nuts/studs and Volvos torque sticks that I'm referring to are specifically for lug nuts/studs only. The Volvo torque sticks for lug nuts/studs is shown as a special tool in every OEM Volvo service manual regarding anything where lug nuts/studs are removed. That's the ONLY purpose where Volvo allows their useage and 10 yrs ago when they first showed up, I too questioned their use but was re-assured by VCNA that they work great with no problems.
I do not use generic torque sticks for anything else as you mentioned, for those things I use a torque wrench.
|
|
-
|
|
|
If these torque sticks are so accurate, then why won't you use torque sticks in other applications?
|
|
-
posted by
someone claiming to be Frank
on
Tue Jul 23 13:21 CST 2002 [ RELATED]
|
|
Because even IF they're not as accurate as a calibrated torque wrench, using them on lug nuts has NEVER been a known problem to me or anyone else I've talked to over the years since Volvo supplied them to us 10 yrs ago.
Why don't people you know use them? I don't know. I've also heard some say what you're saying but then I hear ALOT of BS in my business so I take much of it with a grain of salt and do what I know works from my experience.
All I do know for a fact is that the tools that Volvo has supplied doesn't give me or the other techs in our area any problems.
Why don't I use them for other applications? For one, these days almost all bolts that really require equal torqing at all all get angle torqued (unlike years ago) SO one then needs to be exact when doing critical work like engine repairs (say torquing a cyl head) because it starts out at low torque (not impacted) and then gets angle torqued to incredible tightness. It's seemingly so tight that one's almost afraid that the threads might give way SO accuracy is very important there. I also don't own a set of torque sticks as sold by tool distributors. I use the tools that Volvo supplied us with and is required, mentioned in all their OEM service manuals. Maybe they're better than what one can buy elsewhere?
Volvo requires the lug nut torque sticks as a Volvo shop tool and since they've been in use, I have yet to hear of a specific problem with lug nuts or warped rotors from their use.
Again, I use the one for 700s (65 ft lbs) on my 745T everytime and I've owned that car 8 yrs now. As you might know, 700s were notorious for warped rotors in their day so accurate torquing was essential. My rotors don't warp.
The 850s on up have not been as critical on accurate wheel torque as the 700s were and although I don't condone it, I've seen many a non-Volvo tech (one who doesn't know better) use a standard impact socket on 850s, etc w/o the rotors ever warping. How would I know? We have regular customers who only bring their cars to us so I'd know if one of their cars had a warped rotor problem after someone rotated wheels.
|
|
-
posted by
someone claiming to be Frank
on
Mon Jul 22 16:12 CST 2002 [ RELATED]
|
|
If someone at our dealership replaced rotors and they warp again within the duration of their Volvo parts warranty (assuming you had OEM Volvo rotors installed at a dealership?), then it'd be covered by Volvos parts warranty at no cost to the customer. All Volvo parts have a 1 yr, unlimited parts warranty.
I don't care if the bolts were improperly torqued (almost impossible to prove anyway) or you did drive with the e-brake on (highly unlikely), it'd be covered 100% at our dealership w/o any BS.
I'd be carefully checking caliper pistons to be sure one's not sticking as that's more likely than the other guesses.
|
|
-
|
|
|
Sounds like either one they were over torqued, or be you did not season the rotors. Could be a thousand things though. Sorry to hear f your back luck.
|
|
-
posted by
someone claiming to be Rich G.
on
Mon Jul 22 16:18 CST 2002 [ RELATED]
|
|
Update
The dealer machined the rotors which is a compromise. However, they did not charge for this service tho` I still think the rotors should have been replaced gratis. Apparently, my wife was told to drive to drive the vehicle for a couple of weeks & if the judder returns, bring the car in & they will replace the rotors. Huh? Why not just replace them now & save us the inconvenience of having to return the car again.
Thanks for the input!
Rich
|
|
-
|
|
> The dealer machined the rotors which is a compromise.
You mean they turned the rotors???
Is this a Volvo dealer???? Volvo does not allow turning of the rotors AFAIK. It simply doesn't work.
Get them to install a set of new ones.. And make sure they thoroughly clean the mating surface between the inside of the rotor and the wheel hub. Any dirt or rust there will cause problems with excessive runout or warping.
Bye, Arno.
|
|
-
posted by
someone claiming to be Rich G.
on
Tue Jul 23 05:33 CST 2002 [ RELATED]
|
|
Another update:
Yes, the car was serviced at the local Volvo dealer in Calgary(Valentine Volvo)
And yes, the rotors were turned.Is this contrary to Volvo`s policy on rotors?
Thanks,
Rich
|
|
-
posted by
someone claiming to be Frank
on
Tue Jul 23 13:33 CST 2002 [ RELATED]
|
|
Volvo does not EVER advise that their rotors be machined, it's against their policy, period.
Volvo rotors (same with BMW, MB, Jaguar and probably more) MUST be replaced if warped or damaged. They can physically be machined but it usually doesn't take long before they'll warp again, even if hand torqued ;)
|
|
-
posted by
someone claiming to be Karl
on
Wed Jul 24 17:00 CST 2002 [ RELATED]
|
|
3he problem now is that if a dealer machined OEM Volvo rotors which could have been submitted before for "parts warranty", they can't do that now as they voided the warranty by machining those parts which is not an acceptable proceedure to Volvo.
If they warp again in the near future (likely too), that dealer will not be able to warranty those rotors now (their fault) and they will have to "eat" the new rotors and labor if they want you to be a happy customer.
|
|
-
posted by
someone claiming to be KC
on
Mon Jul 22 09:32 CST 2002 [ RELATED]
|
|
It has been suggested here that overtightening of lug nuts can cause the rotors to warp. Mine warped within a month of a service appointment which included a tire rotation. Granted, I got new rotors under warranty, but now I double check the torque any time I get work done.
|
|
|
|
|
