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Automobile brake maintenance question
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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA

2/17/13 10:14 AM

Me Too


quote:
I've used engine braking on manual transmissions since 1972, and have never had a manual transmission failure or repair. The highest mileage I've had was just under 200K. Every time you let off the gas in a manual vehicle you are engine braking.

My experience exactly. I've had four manual transmission cars, all of which went well over 100,000 miles and the highest almost 200,000 miles. I used engine breaking extensively with all of them and I live in a very hilly area. Not one of them ever gave the slightest transmission problem.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5094
Location: Nashua, NH

2/17/13 3:23 PM

I've never heard of a lifetime warranty on rotors

They do it on pads all the time, but it's just a gimmick, since they soak you on the labor and always try to sell you other unnecessary work. They'll tell you that you can't have the lifetime warranty on the pads unless you replace the rotors and they always seem to find at least one caliper that's "sticking" and has to be replaced, too.

I worked in the under-car service industry briefly and I was absolutely appalled by the scams and thievery that goes on. The guy I worked for was by far the most disgusting, dishonest hypocrite that I've ever met and I took the first decent job I could find to get out that business.

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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA

2/17/13 4:05 PM

Lifetime Warranty

Agree on the scam aspects. I recall the "lifetime warranty" on mufflers in the past and, while they would give you a free muffler, somehow all of the clamps and pipes had to be replaced too and they were more than the muffler cost by a lot.

I once got a "lifetime" muffler but just bought it in the box and installed it myself. When it eventually rusted out I took it and the warranty card back and insisted on a free replacement. They gave me one but were not happy about it at all.

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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven

2/17/13 7:37 PM

I was talking about parts stores and carry out parts. heres a link to lifetime warranted rotors for my vehicle, a Honda Element. I'm pretty sure they also have pads that are warranted to last forever.

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_brake-rotor-only-wagner_19200366-p?navigationPath=L1*14921|L2*16462

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5094
Location: Nashua, NH

2/19/13 5:54 AM

Where do you see a lifetime warranty?

Maybe I'm just missing it, but the only warranty information I found on the site indicates that it's 90 days.

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5094
Location: Nashua, NH

2/19/13 5:57 AM

Lifetime warranty on exhaust

The main part of the exhaust scam is that they don't use clamps, they weld the system together, which means that when the muffler goes, all the pipes have to be replaced too, since it's all one unit. They also use cheap pipe that will rust out around the same time as the muffler.

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dfcas
Joined: 11 Jan 2004
Posts: 2815
Location: hillbilly heaven

2/19/13 8:57 AM

Sorry,that link did not have warranty details. Take a look at the 3rd or 4th rotoe down.

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/PartSearchCmd?storeId=10151&catalogId=10051&pageId=partTypeList&suggestion=&actionSrc=Form&langId=-1&searchTerm=brake+rotors&vehicleIdSearch=293641&searchedFrom=header

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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5094
Location: Nashua, NH

2/20/13 5:53 AM

Still nothing

Perhaps the site presents different information based on location, but I don't see any warranty info specific to the rotors, just the generic Advance warranty info.

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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA

2/20/13 11:45 AM

Question


quote:
In manuals, it puts a lot of strain on the gears in the opposite direction that they are designed to work in, which if nothing else, increases the wear on them.

In an automatic, you have the additional concern that you can cook the transmission fluid which will trash the transmission. A transmission oil cooler can help, but at slow descent speeds, it may not be enough.

I've been thinking about this and am puzzled.

Your first claim, as my own, dfcas's and many, many others experience has shown, may be a theoretical consideration but is meaningless in real world driving.

Can you explain your second claim? Why does operating an automatic transmission on the overrun heat it any more than when it is driving the wheels? Why would going down a grade locked in 3rd gear cause any more heat than climbing the same grade in 3rd gear? Auxiliary transmission oil coolers are recommended for heavy duty applications like towing but that's because the transmission has to handle a larger load while pulling, not so much retarding the load.

In the past, towing a car with an automatic transmission was a hazard if the drive shaft wasn't disconnected because the transmission oil circulation pump was on the drive side of the gear train and there was no circulation if the engine was off. There were cases of the transmission fluid boiling and bursting the housing and in one instance I know about a couple of people riding in the towed car (illegally) were killed. That isn't true with current designs and certainly isn't true if the engine is running at all.

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dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

2/20/13 1:22 PM

When it comes to heat buildup, the biggest worry is the one "big event" in the tranny's life where the temp reaches an all-time high.
That would be a near-full-throttle pull up an extended grade in hot weather.

The power going into a tranny during decell would normally be a lot less than that, but beware if the hill is truly that long (miles) and steep.
Except that most of today's automatics use the engine's cooling system with a fluid-to-coolant heat exchanger, so the tranny gets some relief at a time when the engine isn't dumping much heat into the relatively large (for the transmission) cooling system.
As well, the engine (going uphill) has to produce power to overcome rolling friction and air resistance, while going downhill those two parasitic losses actually reduce the power load going into the tranny by the same amount.

What I don't do is use the shifter for anything approaching a normal stop. The impact loading and wear to the shifting mechanism, gear dogs and clutch+throwout bearing would seem to be more economically substituted with normal use of the brakes, yet I see the occasional stick driver who seems to like the arm and leg workout aspect of downshifting to ostensibly "spare the brakes".
What I do is at least change the transmission oil (my truck uses plain 5w-30 in the gearbox) at the prescribed 30k interval, and I can say that my original clutch, transmission and all eight brake pads/shoes are still in the game after 24 years. There are some very steep hills up here which I use the transmission to assist with handling the downgrade using either 2nd, 3rd or sometimes 1st gear, with perhaps two or 3 shifts for the entire downgrade, and with the motor speed approaching "highway" rpm's.

My front rotors developed a variation of thickness condition at 15k that caused bake pulsation, and since I lived quite far away from the nearest Izusu dealer I just pulled them and had the now "heat- and stress-seasoned" rotors turned locally. One of the bearings had become frozen onto the axle, so it was destroyed during removal and I had to ride my MC to the far-away dealer and pay for the replacement bearing (grrrr). But the turned rotors have resisted any kind of warpage or uneven wear in the following 22 years.

I once had the Midas "lifetime" muffler installed back east, and it proved to be relatively short-lived compared to the OEM part.
When I went back for a replacement, sure enough the pipes and install cost nearly as much as a competing shop's full system replacement.

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Dave B
Joined: 10 Jan 2004
Posts: 4511
Location: Pittsburgh, PA

2/20/13 1:46 PM


quote:
What I don't do is use the shifter for anything approaching a normal stop. The impact loading and wear to the shifting mechanism, gear dogs and clutch+throwout bearing would seem to be more economically substituted with normal use of the brakes, yet I see the occasional stick driver who seems to like the arm and leg workout aspect of downshifting to ostensibly "spare the brakes".

Agree that abuse is abuse. I would always "double clutch" and "rev match"downshifts when I wanted engine braking with a manual transmission and that avoided severe loads on the synchronizers and clutch.

Along with my four 100,000+ manual transmissions that never needed any repairs, I never had to replace the clutches in any of these cars either.

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