Stop here! Let's talk about brakes

Mr_Shiftright

Sounds like an internal leak in the brake master cylinder.

Are you losing fluid at all?

Have you bled the brakes lately?

alcan

What year van? Does the check engine light come on? If it has rear wheel antilock brakes, the dump solenoid in the hydraulic modulator can leak, allowing rear brake pressure to bleed into the accumulator. To diagnose, remove the rear line from the master cylinder and install a block-off plug. If the pedal still goes down the leak's in the master cylinder, if not it's the hydraulic modulator.

Mr_Shiftright

That's a good test, thanks, for isolating the problem. He didn't mention the engine light going on, so I didn't think of the ABS system.

Auto parts stores usually have those little brass plugs.DON'T DRIVE WITH ANYTHING DISCONNECTED!!!

jrichman1

its a 1992 does not have anti lock brakes! the same light that comes on when the emegency brake is on, is coming on when it loses pressure. i havent noticed any loss of fluid. last time i bled them was 6 months ago when i changed the front brake calipers

Mr_Shiftright

So, if you have no leaks, no ABS, and you are losing pressure then you probably have a bad master cylinder. Air in the lines wouldn't explain this "on again off again" condition.

jrichman1

how much would this tipically cost to get fixed?

Mr_Shiftright

Well depends mostly on how difficult it is to get it out. It's probably a $300 job at least I would think.

Marty684

I usually wash my car in the evening and it immediately goes into the garage where it may sit for a day or two.

My question is - should I drive the car for a mile or so after cleaning the wheels so that rust doesn't build up on the brake system or is it ok to continue to do what I have been doing?

ruking1

To me 6 of one half doz of the other. Since my driveway is on an incline I have to function the brakes as part of the process of moving it into the garage. (upshot no rust build up on the brake disc surfaces) The other thing about moving the car a bit is that it can let gravity help the h2o out of the cracks and crevices that it always seems to find itself.

bpeebles

No question.... DRIVE IT!

At the very least, the brakes should be used enough to get warmed up to drive off the moisture. Also, driving will tend 'wiggle free' water that has puddled in unseen places. I often make it a point to get on the highway and drive over 60MPH to the next exit....but the above is only "between" real wash-waxing sessions.

It really depends on your automible maintenance procedure. When I wash with intent to wax, I use the following procedure:

Wash with Zymol auto wash
Rinse well
microcloth to lift the stubbern stuff (bugsplatter)
chamious to dry the surface
Apply Zymol wax in back-n-forth pattern (use LOTS of muscle to force wax into paint pores!)
Buff with orbital buffer
Use toothbrush in nooks -n- crannies

At that point, the paint surface appears about 3 feet "thick" (as measured with a yardstick).

Personally, I do not like "polishes" that make the surface shiney... it looks "plasticky" ,does not protect from rain-n-snow-n-ice and does not last.

jrichman1

thank everybody you guys were right . it was the master cylinder. costed me 289.00 for replace master cylinder flush brake fluid and ajust and claen back drum brakes

bpeebles

Did you know that regularly replacing your brake-fluid is far cheaper than waiting for the moisture-buildup to ruin the master-cylinder, ABS components or wheel-cylinders?

Brake fluid is basically the same chemical formula as your antifreeze. It is designed to be Hydroscopic (attracts water). After about 3 years of use, brake-fluid gets saturated with water and then your brake-system starts to corrode from the inside-out

For this reason, most automobile manufacturers suggest replacing the brake fluid regularly.

BTW: There is such a thing as "DOT5" brake fluid which is basicly silicon oil. This stuff is totally impervious to water. The problem with it is that any water in the system will just sit in the low spots and corrode things even faster than "DOT3" or "DOT4" fluids. So, conventional wisdom says that it is BETTER to have a brake-fluid that attracts water abd holds it in suspension.

Mr_Shiftright

I flush every two years. I can't even remember the last time I replaced a master cylinder. Oh, yeah, now I do. Saab turbo, ate 'em like candy.

bpeebles

It sounds as if those turbocharged brake-cylinders wear out really fast ;-)

Perhaps you should have tried cross-drilled brake lines ;-)
http://www.kalecoauto.com/perf.htm

Mr_Shiftright

Hey, some good products there! I'm planning to market a new line of "brake socks" to go with the normal brake shoes.

wtd44

bpeebles: I simply do not believe in coating wax over perfectly beautiful paint on "recent" vehicles. The clearcoat does not need it, and in fact, may lose some longevity from it.

Mr_Shiftright

oops, wrong topic for wax talk!

Let's stay on course please.

wtd44

That's an excellent idea. One might wax prolific, but given an adequate brake, the proper channel may be navigated.

Some years back, a colleague of mine advocated the replacement of (at least) front disk pads routinely at 30K intervals. He claimed to never resurface his rotors. I am giving thought to trying that very thing on my Villager. Do you predict any particular problem? I suspect it just might work out.

isellhondas

The way I drive, my front pads will usually last twice that long or more. To me, that would be like pulling into a gas station with a half tank og gas then dump the half tank down the drain and fill it up.

Mr_Shiftright

I don't see the point unless MAYBE you have a car without a brake lining warning light.

ruking1

To me it is just far easier to remove all doubt and just LQQK at it!!

wtd44

My friend, being a DIYer, was able to simply pop new pads into the calipers again and again, while never having to turn the rotors. He thought that most rotor damage was due to long standing use of pads that grooved the rotors, but if you put in new pads often enough, the grooving could be minimized. I never really investigated his idea, but after some of the "hard luck" I've had in very recent years with brake jobs that are done when they really need to be, I find his alternative a little appealing.

ruking1

Perhaps the main point: is the rotor within specifications!?

bolivar

My two cents - Rotors and brake drums with significant ridges and gouges can take new pads or shoes and give satisifactory performance. Probably not maximum possible performance, but ok performance. I think the relatively soft pad or shoe material will quickly conform to imperfect braking surfaces.

Rotor replacement are needed when they are warped. Drums that are cut down, with a ridge on the outside edge also require turning. And either should be replaced when worn down past the minimum specifcation.

But with manufactors apparently putting rotors and drums of mimimum quality on new cars, there are not many cars now that will wear out pads without the rotors becoming warped.

needsahemi

I see there is are so many knowledgeable people here so I hope someone can help me on this one. I have a 1999 Corolla and have just had the front brakes replaced (rotors and pads). Within a few days I've started to get a grinding in the front brakes intermittently. Almost always braking while going downhill they grind while applying the brakes, and 20% of the time on flat surface. I have taken the car back to the garage and they just cant find any reason for it, the brakes look good-no pad or rotor obvious markings- Could it be something other than the brakes? I find it rather odd the incline the car is on factors into this. Thanks for any ideas.

wtd44

This is the kind of stuff that has led me to consider changing pads very early and leaving the rotors alone! I went through a series of problems like yours, but on a Nissan Pathfinder. The best I could ever get the brakes to behave after all the various "solutions" was the installation of Raybestos ceramic pads. That gave much quieted performance.

marshella

Hello,

My 2002 Malibu, with just under 40K miles, went in the shop recently for rear brake noise. Turns out what happened was the end piece of the brake-adjuster spring broke off, releasing a piece of metal that embedded itself into the shoe, breaking it to bits, and causing exposed screws to gouge the drum. Fortunately, although the mechanic thought the drum was toast, it was able to be turned satisfactorily.

I'm wondering - could this be a possible manufacturing defect in the strength/integrity of that steel spring, or could the damage been caused by something else?

Should I notify the manufacturer - could this be a potential problem on similar cars, or just my extreme bad luck?

Marshella

wtd44

It certainly sounds like a case of the spring being defective.

needsahemi

Thank you very much for your opinion on replacing the brake pads wtd44. I must say after reading your posts in other forums (and this) I appreciate your opinion. Your a definite asset to edmunds. Thanks again.

wtd44

Many thanks! I bought a new 1997 Geo Prizm in August of 1997. As you know, the Prizm is the twin to the Corolla. They are very good cars. I changed the rear brake shoes once, and did not have the drums turned. In retrospect, I suspect it would have been a good idea to turn them, but all worked out well without that added time and money consumption. I never did have to replace the front pads. They just didn't wear out, and I saw this Mercury Mountaineer that I wanted...

bpeebles

Here is a photo of what my powerslot rotors looked like after 3 Vermont winters. (I snapped this just moments before I took them to the dump and shotputted them into the scrap-metal bin!)

http://hometown.aol.com/peebs4u2/powerslot_after_3winters.jpg

Now, I am running Bendix rotors and time shall tell if they are any better at resisting the winter roadsalt.

As a reminder... the ORIGINAL Dodge Dakota rotors lasted thru only 2 Vermont winters.

wtd44

Really awful! Maybe the best hope for you and others in Vermont would be the state cutting way back on salt and increasing the use of plows. I've never seen anything like that, here in the Rocky Mountain Empire.

bpeebles

I would really LOVE it if the state cut wayyy back on the use of calcide on the roads. Not only would it save mucho tax dollars, it would also allow out vehicles to last more than 8 years before rusting. Also the evergreen trees all along the roads turn brown and die because of the calcide which is automized by the passing cars and settels on the needles..

Unfortunately, there are 2 things working against the reduction of roadsalt.
1) All those people that seem to feel it is their right to sue the state because of their own bad driving habits in the snow.
2) The beurocratic idea that if you do not use ALL of your calcide this year, you may not get allocated the same amount next year.

lumbar

Here's a pretty basic question from someone with not a lot of mechanical knowledge: Is it standard practice among mechanics to machine rotors when pads are replaced? I realize this might be preferable in some instances, but my uniformed impression was that the reason to change pads on time was to save the expense of dealing with the rotors.

ruking1

Both the brake pads and the rotors have an allowable wear rate/specification. Each is measured separately and independently yet obviously can be/are interelated, even though folks might tend to think that only the pads wear. In today's "bean counter" emphasis, there are a lot of oems/vendors that will deliver within much narrower specifications a pad and rotor combination that in effect will probably last past whatever meager warranty is offered for pad and rotors. So when a rotor is "out of specifications" enough so a customer complains about it, a shop or mechanic must make a calculation on whether or not based up the specification and the estimates of how a customer has worn the pad and rotor combination whether the rotor in particular will last as long or longer than the pads. Or if it is just plain easier to change both. So many a time because they don't even want to come close to being liable, they will highly recommend changing both the pad and rotor. So from a liability standpoint, that puts the driver and the oem of the pad and rotor in the "drivers" seat so to speak and not the judgement of the mechanic, whose rotor and or brake pad might have failed (causing a crash) trying to save the customer money.

wtd44

And unfortunately, many of the newer brake systems are not "responding" well to pad replacement with resurfacing of rotors.

ruking1

I would agree. There are bedding procedures, but I am thinking the average person is not aware or more like COULD NOT BE BOTHERED. So of course, what happens- happens?

For me, I had a 1987 Toyota Landcruiser that went through three sets of pads ( 1 oem and 2 PBR's if anybody cares? ) before a resurface/rotor change was even a need/requirement (60,000 per pad set) This was a daily driver, but more importantly did double duty as a business client sales/delivery vehicle also!!

On a VW Jetta TDI, I am facing the same issue, whether to just change both pads and rotors when they are due and/or measure/calculate and reuse the old rotors. Technical data indicates a measure and reuse procedure. Projections indicate I can reuse the rotors. However, the good news and bad news is the fact that the rear pads tend to wear faster than the fronts. Some VW techs say change the rotors with the pads!! So I am projecting 90/120k miles rear pads and beyond that (120/150k) for the front pads. So in a way, it is like two separate brake pads and rotors changes. So down the line ( I am at 45k miles now) I just might wind up changing one set of rotors with pad change and/or just doing a pad change, or just change the pads and rotors at the same time. : (

lumbar

for the replies. I've been lucky enough to not have replaced the OEM pads on my Subie for 6+ years and am not familiar with current practice. My mechanic informed me (after the fact) that he -always- resurfaces rotors when replacing pads in order to be able to "guarantee" the job. I was wondering if his view--that it's sort of a package deal--is how its done.

ruking1

Ah, correct me if I am incorrect but he is zeroing his run out. My guess is that the Subie's rotors have enough material left to handle the "second" set of brake pads at the projected prior wear rate. Normally the best is (not sure of the Subie term, so convert to Subie eze. )to use a 3300 dollar "on-car brake rotor lathe".ie made by Kwik-Lathe for "squareness", trueness and maximum surface area to ensure a correct machined surface that meets or exceeds oem specs.

bpeebles

(limbar) Many mechanics ALWAYS resurface the rotor at pad-changing time. They often say that they will not "guarantee" their work if you ask them not to resurface. It is a way for them to get some $$ out of their expensive rotor-lathe.

This unnecessarry removal of surface material is most often wasted $$ and just takes life off of the rotor. (by making it thinner and more susceptable to warpage.) Also, many modern rotors are NOT SUPPOSED TO BE MACHINED because they are hard-surfeced and the softer inner metal may be exposed.

Under normal circumstances, just changing the pads is just fine. The new pads do not "care" if the rotor is perfectly smooth. Any scars in it will be concentric so they will not increase wear on the new pads in any way.

Of course, if the rotors are beyond wear-tolerance, then that needs to be addressed.

alcan

Here's GM's position on rotor refinishing for all their vehicle lines:

Brake Rotor Refinishing
Do not refinish brake rotors when performing routine brake maintenance such as replacing worn disc brake pads. Refinish a rotor only under the following circumstances:

There is a complaint of brake pulsation.

Important
Do not use a brake rotor that, after refinishing, will not meet the specifications shown on the rotor. Always replace the rotor with a new rotor.

There is scoring greater than 1.5 mm (0.060 in). All brake rotors have a minimum thickness dimension cast into them. This dimension is the minimum wear dimension and not a refinish dimension.

Accurate control of the rotor tolerance is necessary for proper performance of the disc brakes. Machining of the rotor should be done only with precision equipment. Machining equipment should be serviced on a regular basis following the manufacturer's recommended maintenance procedure.

wtd44

When changing old disc brake pads for new, do you think that the surfaces of the rotors should be "roughed" or "randomized" with abrasives such as emery cloth to break up any directional grooves? I ask this due to previous advice from the local NAPA outlet. With all I have read lately, I am getting close to simply changing the pads on the front of my 2000 Mercury Villager with no attention to the rotors at all. Visually, the rotors look fine, while the pads are getting thin.

ruking1

The best answer is to compare the rotor to the technical specifications. The next tell tale sign is how the old pads have worn. (outside of just being thin)If the pads are smooth, even, with no scoring on the rotors, you now have a few more data points on which to base your conclusions. Given that things are ok I would not "randomize the rotors" but simply follow the em's bed in procedures.

dhoff

Regarding the brakes on your 00 Villager... I've done 2 brake jobs on my 99 Quest (identical) and I bought new rotors and pads both times because my rotors were warped. If yours aren't, what you propose might be worth a try.

This last time I ordered new pads (Satisfied Pro Ceramic, they suck, don't buy them) and rotors (Brembo, so far so good) from Tire Rack. The first time I got OEM Nissan parts and I had no complaints.

Dave

wtd44

Many thanks for your info and thoughts. When I had the passenger side front wheel off to get access to the bottom of the windshield washer reservoir, I noted that the original pads in that caliper looked worn down to where I should pay attention. We have 24,400 miles on the vehicle. How long do you suppose the average mileage potential might be on Quest/Villager original front pads?

alcan

Roughing or sanding rotors is only done after machining, to avoid brake squeal. Even the best machining equipment cuts a very fine thread into the rotor, and this directional finish MUST be removed. If you're just replacing pads, make sure there's no corrosion buildup on the outer edge of the rotors in the area not swept by the pads, use high quality pads such as Raybestos PG Plus or Quiet Stop, lubricate the caliper pins with silicone grease, and you're good to go.

Specs are:
original rotor thickness 1.024"
minimum machining thickness .975"
discard thickness .945"
lateral runout .003" max
thickness variation .0004" max
caliper to bracket 29 ft/lb
wheel nuts 80 ft/lbs

ruking1

Assuming these are the required specifications, this illustrates the problem and opportunity with reusing the same rotor/s and/or one axle set of rotors x 2. The difference in original rotor thickness of 1.0024 and the discard thickness of .945 is .079 in. The metric conversion is actually 2 mm.

So for example, if you can get 60,000 miles on a set of pads with some pad material left to go, and you use MORE than one MM, on the rotor; then if you anticipate 60,000 miles on your (2nd set of ) new pads, your rotors are projected to be PAST the discard thickness if you go 60,000 miles and or more!!! . This can of course have catastrophic consequences!!!. Now keep in mind you should do this for each axle changed, so even if one side is good the other side can easily cause you to change the rotors.

Conversely if the 60,000 miles on the pads use less than 1mm on the rotor, then both your new pads and rotors are projected to wear out about the same time at the 60k mile mark for the (2nd set) new pads and app 120,000 for the old rotor.

alcan

"Assuming these are the required specifications"

I don't make assumptions re specs. The numbers I posted are from the current Raybestos Disc & Drum Brake Spec book, which I refer to during every brake job and vehicle safety inspection I perform.

"Conversely if the 60,000 miles on the pads use less than 1mm on the rotor, then both your new pads and rotors are projected to wear out about the same time at the 60k mile mark for the (2nd set) new pads and app 120,000 for the old rotor."

Not necessarily. Look at the difference between minimum refinish spec of .975" and discard spec of .945". By my math Ford wants .030" left for wear, which clearly indicates they don't anticipate more than .030" wear of the rotor surfaces to take place during the service life of a set of pads. These numbers are fairly generous, as most manufacturers specify .015"-.020" to be left for wear after rotor machining.

ruking1

I hope you did not think that I was dissing what you were saying in any way. While I am sure that what you are saying is true, it is entirely possible the oems shop manual might be different. I have been around jet aircraft and missiles and space etc specifications far too long to know that there are and can be variances, additions, deletions, and changes to say what I said.

One part of "not necessarily" IS "Projection." Again this is why I say that some mechanics and or shops recommend just changing rotors with brake pads.

wtd44

Many thanks for the information. I have copied and saved the specs on my computer desktop, and I will reference them when the time comes. Given that my Villager is closely a Nissan vehicle (made by Ford), and that my now traded off Pathfinder was a Nissan vehicle, and further given the trouble I had with a brake job on the Pathfinder, I have equated the Pathfinder brake system to that found in the Villager, and thus conclude that indeed Raybestos Quiet Stop should be procured for this pad exchange. (:o]