What are some car-repair jobs you always wished you could do but have never done?

On 6/11/2017 3:05 PM, Frank wrote:
> On Sat, 04 Nov 2017 02:42:59 +0000, RS Wood wrote:
>
>> What are some car-repair jobs you always wished you could do but have
>> never done?
>>
>> Mine are, in this order of "I wish I could do it" order 1. painting 2.
>> alignment 3. replace/rebuild engine 4. clutch replacement 5. tire
>> mounting and balancing 6. timing belt 7. head gasket and vcg
>>
>> I've done electrical, brakes, shocks, cooling systems, alternators,
>> ujoints, pitman/idler arms & tie-rod ends and ball joints, tuneups,
>> emissions hoses and sensors, exhaust, electrical components, fuel pumps,
>> and fluids, but not the six things above.
>>
>> What are some car-repair jobs you always wished you could do but have
>> never done?
>
> I've never painted a car. I suppose some day I'll give rebuilding an
> automatic transmission a shot, but I've been lucky so far.

Lots of traps for the unwary in that little task.
>
> I've done things ring and bearing jobs but everything is holding up
> better nowadays.
>


--

Xeno

wrote:

> Some of the best rotors out there are Chinese - but also some of the
> worst. Consistency is the problem

I can't argue but my point is that I've heard everything.
The problem is that the advice has to be both logical and actionable.

Saying "buy only Brembo or Meyle" is actionable, but not logical.
Saying "don't buy Chinese crap" is logical but not actionable.

For advice to be useful, it has to be both actionable and logical.
I've never heard that in rotors other than buy solid and don't buy
drilled/slotted rotors.

Other than that, there's no way for a person to tell if one rotor is gonna
be better than another.

Hence pragmatically ... a rotor is a rotor is a rotor is a rotor.

> In some instances (virtually never normal street use) grooved and
> slotted rotors DO provide better braking. We are talking competition
> use, where the rotors are glowing red hot half the time, and the pads
> are off-gassing like crazy - where even 100% dry DOT4 brake fluid
> boils in the calipers. Under those conditions, rotors can warp - and
> even fracture (in Rallye use I've seen red hot rotors hit an icy
> puddle and totally fracture)

I'm never talking racing.
They drive on bald tires for heaven's sake in racing!


> Actually, on SOME cases you can. Look at the consistancy of the fins
> in the rotors, and the even-ness of the thickness of the braking
> surfaces on both sides of the fins.

I'm not gonna disagree that we all can see the mark of good quality on some
things when we have two to compare in our hand, but it's too late if you
order on the net.

>>How are you gonna know the metallurgy?
>
> You don't - that's the hard part - but when you are in the business
> you get to know which suppliers stand up, and which don't. If you
> know the suppliers well, they will tell you which ones they have
> trouble with, and which ones they don't.

Yup. I have nothing against good suppliers. I use Brembo and Meyle but if
someone else gave me a rotor at a better price, I'd consider them too.

> And some rotors DO WARP. Not many - but I've had at least a bushel
> basket full of genuinely warped rotors in my 25 year carreer. Most
> "warped" rotors are not warped - but some are. Some DRASTICALLY - to
> the point the caliper moves visibly when the wheel is turned - and if
> the sliders stick the pedal jumps and the steering wheel twitches.

That's not the measure of warp.
Warp is measured on a flat bench.
Just like head warp is measured.

> More often than not though, they are either pitted or have deposit
> buildup, ot they have "hard spots" due to metalurgical inclusions

The only person who says their rotors warped that I will ever trust is one
who measured the warp just like you'd measure head warp.

If they haven't measured it, it's not happening.
And nobody measures it.
So it didn't happen.

It "could" happen. But it doesn't (on street cars).
The problem is the temperature never gets hot enough.

Now they can be "warped" from the factory; but that's different (and rare).

> Wrong tool. The one I'm talking about has tabs that fit into the
> notches on the piston face to "thread" it in as you squeese. Can
> sometimes get away with the $17 "cube" but the kit you KNOW is going
> to work starts at about $35 for one of questionable quality, and goes
> up very quickly from there (and IT won't turn back Mazda rear calipers
> - they use a different system

I think we're talking about two different kinds of disc brake systems.
I had the Nissan 300Z which had the rear disc also as the rear parking
brake, but my bimmer has the rear disc and a separate rear parking brake.

The piston arrangement is different as is the way to retract them.

You don't *twist* pistons in disc brakes that I own that don't have the
parking brake as part of the disc brake itself.

At least I don't.


>>Never once in my life have I found a single person who has *measured* the
>>warp.
>
> I have. many times.
How?

>>You know why?
>>They don't even know *how* to measure rotor warp.
>>They don't have the tools to measure rotor warp
> A somple dial indicator tells the tale

Nope.
How you gonna tell runut from warp with a dial gauge?

> - and sometimes one side is
> straight, and the other side is not - parallelism warpage - where some
> fins collapse and one side of the rotor "caves in" - 1 inch thick on
> one "side" of the rotor, and .875 or something like that diametrically
> across the rotor. - and sometimes virtually deead flat on both
> surfaces - other times with about hald paralel and the other half
> "sloped"

Now you're straining credularity.

>>(Hint: It requires a flat benchtop and feeler gauges and it's not hard -
>>but they don't know that because they didn't measure a single thing.)
>
> That won't necessarilly tell you anything. The only way to KNOW is to
> use a dial indicator properly.

How you gonna tell runut from warp with a dial gauge?

> And that is where YOU are WRONG.
> Many technicians measure brake rotors virtually every day of their
> working lives.

On the entire freaking Internet, find *one* picture (just one) of a
technician actually properly measuring brake rotor *warp*.

Just find a *single* picture please. Just one.
On the entire freakin' Internet.

Find one.

> Dealerships were then REQUIRED to buy an "on-the-car lathe" to true
> up rotors.

That's not warp.
Nothing on this planet is going to fix warp.
There's not enough metal to remove.

> A wize man learns from the mistakes of others - a fool never learns
> because he "never makes mistakes"

Which is why I wish I had done these half-dozen jobs:
1. Alignment
2. Transmission
3. Engine
4. Tires
5. paint

> Yes - you are right to the extent that MOST "warped rotors" are not.
> But you are absolutely WRONG when you say they never warp in
> street/highway use and anyone who says they have had a warped rotor is
> lying and hasn't measured the rotor to prove it.

I never once said "never" but "almost never" which is different, and we're
only talking street, and I have references that back up everything I say
whereas you provided zero references for what you said.

I'm not here to argue opinions.
I only argue using logic.

Just read the references I provided and then provide some references that
back up your point of view.

The "Warped" Brake Disc and Other Myths of the Braking System
<http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths>

The 'Warped Rotor' Myth
<http://www.10w40.com/features/maintenance/the-warped-rotor-myth>

Warped Brake Rotors - Vibrating Reality or Internet Myth?
<https://blog.fcpeuro.com/warped-brake-rotors-vibrating-reality-or-internet-myth>

Stop the +IBg-Warped+IBk- Rotors Myth and Service Brakes the Right Way
<http://www.brakeandfrontend.com/warped-rotors-myth/>

Raybestos Brake Tech School, Part One: Rotors Don't Warp
<http://www.hendonpub.com/resources/article_archive/results/details?id87>

Xeno wrote:

> Any scoring on a rotor will fail it. As you say, there might be less
> than 50% of the pad surface in contact with the rotor surface. No way
> will that bed in properly. You will get localised overheating both on
> the pad and on the rotor.

I'm not gonna argue vehemently because, in practice, while I've seen those
"wavy" rotors too, my rotors tend to be smooth so I don't deal with
"scoring".

However, anyone who says "any scoring of rotors will fail it" has NOT looke
up the manufacturer's spec for scoring tests.

I have. Long ago.

The result was shockingly huge.

I don't remember the actual number but I remember being shocked at how huge
it is. Something like tens of thousanths of an inch in width huge.

We're talking Grand Canyon in rotors.

I may be wrong but if someone says "any" scoring, that's just preposterous.
Let's see a manufacturer's spec for anyone who says that.

Sorry. It's just not logical that 'any' scoring fails a rotor.

The Real Bev wrote:

>> If the vibration decreases, or markedly changes character, or even goes
>> away, then how could it possibly have been rotor warp in the first place?
>
> I wish I could remember when I stopped noticing it. I might have done a
> hard stop to test whether the seat belts were still working properly...

It's impossible to diagnose brake-related judder/shudder/vibration on the
Internet - but - most of the time - the cause is the simplest most obvious
reason.

You drive hard on the highway and then stop hard at the bottom of an exit
ramp at a light where you sit there with your foot on the brake for a
period of time.

Guess what happens?

For a hard-to-understand reason, the teeeniest tiniest pad imprint tends to
grow over time. I don't really understand why, but it does. It gets almost
imeasurably larger over time, until you finally feel it while braking at
speed.

What's the solution?
Simple.

SHORT TERM: Scrape that deposit off.
LONG TERM: Change your braking habits.

>> Q: Is a $50K rolex watch a better watch than a $30 Timex watch?
>> A: The watch that keeps better time is the better watch.
>
> Ha. My $25 Casio atomic solar watch has been providing accurate time
> since 2008 with no attention whatsoever. The beautiful 195x Omega
> Seamaster is sitting in a box somewhere because it needed to be cleaned
> every couple of years. Apparently the lubricant breaks down -- it
> doesn't seem that dirt could get into a waterproof watch. I guess it
> was accurate, I didn't have anything to check it against but the nice
> lady on the phone who told me the time.

I have a few Rolex watches (most received as gifts).
They suck at keeping time.

For brake pads, the thing you care about is friction, cold and hot.
Nothing else is close in importance (although dusting is key for some).

So pick your pads by what the OEM pads were and try to meet or exceed that.
Most pads are around FF but every pad says what it is or it can't be sold
in the USA.

The (SAE J866a) charts are all over the net.
Just look for 'brake pad friction ratings' or something like that.

> I drive roughly 4K miles/year and front pads on other cars generally
> were OK for 40K miles (rear shoes double that). ~20K now. I'll
> remember this just as long as I can :-)

Life is one thing but the *primary* factor in brake pads is friction.

I buy $35 PBR pads with FF or GG friction ratings which last 30K miles or
so and the dust isn't objectionable.

So my factors a
a. Friction rating (anything less than FF is worthless)
b. Non-objectionable dust (the only way to know is to ask owners)
c. Decent life (the only way to know is to ask owners)

Friction Coefficient Identification System for Brake Linings
<http://standards.sae.org/j866_200204/>

wrote:

>>Adjustable wrenches should be banned as a menace to society.
> They are totally fine for some applications - but NOT bolts on a
> car!!

I was joking, but I still don't get why I see people use them all the time
when they slip too much because they fit so badly and only on a few edges
and they are huge compared to the right-sized box wrench so they don't fit
in a car.

I'm gonna start a "Save the bolts" non-profit political group to enact
stringent adjustable-wrench control laws!

One rounded bolt head is too many.

wrote:

>>I just wish I could have done that on my own, without paying $100 for
>>someone else to twist a bolt that I could have twisted myself.
> You paid $10 to twist the bolt and $90 to know how far to turn what
> bolt in what direction!!

Good point.
But I would rather have paid $100 for the tool to measure to know that I
twisted the bolt as far as it could go.

In the case of my rear camber, it was maxed out at 0 degrees, so, in
hindsight, I guess I could have done it sans any measurement at all.

Xeno wrote:

>> Lot of us keep a car until repair cost exceeds book value.
>
> I trade my cars in when I'm sick of them.

For me, I get a new car when the old car has a repair that isn't worth
paying. That's less likely nowadays as I'm retired on a low budget.

wrote:

>>What's so great about gasoline direct injection anyway?
>><https://www.cnet.com/roadshow/news/whats-so-great-about-direct-injection-abcs-of-car-tech/>
> The biggest advantage is the fuel is injected after initial
> compression, just before the spark - so the fuel is not "dwelling" in
> the combustion chamber under high heat and pressure, dissassociating
> and causing detonation. Can run much higher compression ratio on
> regular gas.

Thanks for summarizing the most important advantage.
I've found that anyone who can't summarize the most important factor
generally does not understand the issue.

So thank you for summarizing what is new information for me.
Much appreciated!

wrote:

>>So, fundamentally, people seem to be saying that carburetors contaminated
>>everything more than does EFI, which reduced the life of the engine.
>
>
> Correct

Thanks.
Makes sense.
I love learning where the lesson makes sense.

Frank wrote:

> 10W 40 would coke up faster than 10W 30, for what it's worth.

I just mentioned that, but I didn't look for references.
Do we all generally agree that the *spread* is what causes the coking?

0W30 has a spread of 30
5W30 has a spread of 25
10W40 has a spread of 30
30W40 has a spread of 10 <--- this has the lowest coking

If we agree on that concept of coking:spread, then the question is how much
does coking actually matter and under what conditions does coking matter?