Only 10K on my MB brakes UGH!

[Sysco Kid]

Am I wrong to question my mechanic?He put new MB brake pads on my 1984 30tdt and after 10k miles and lots of squeeking he says "i need new brakes again"? I've gotten 50-70k betwwen changes when I had a Volvo 850 and can't seem to swallow the news. I'm aware of the softer pads MB uses but this seems way too short a time to have this issue again.

Any thoughts?

Michael

[H-townbenzoboy]

Get a second opinion. Unless you drive down mountains everyday, 10k miles is way too short from regular use. Did he show you wear spots, or did he just come out and say "you need new brakes"? Try another MB specialist and see what their diagnosis is.

[VLayton]

Front back or both? Caliper causing uneven wear? How about brake pad wear warning light? Do you tend to do the majority of your braking in the last few yards? I try to moderate throttle to traffic flow/regulation and utilize the diesel motor's natural drag to do my slowing and slightly longer and lighter braking to my stopping point. Certain hills with stops at the top I can hit perfect full stop with zero braking, it may be an aquired skill of some kind... :rolleyes:

The fronts should last 20-30k mi and the backs about 50-65k mi.

Just my thoughts...

[Don350SDL]

Yeah, I'd want to see the pads myself - they are normally about 1/4" thick with brake material, I would replace them with about 1/16" of material left.

Squeaking is not a reason to replace pads.

[Sysco Kid]

I will get another opinion. I also let the cars natural drag slow down the car as much as I can . It's to the point where I almost challange myself on how little I can actually use the brakes to slow down. :p They are the fronk brakes by the way.
On another note... I installed a new mono valve last week and now "Grease Lightning" is nice and toasty all the time. ;)

Enjoy the weekend

Michael
1984 300tdt

[Johnson Chan]

I use genuine MB brake pads and do not have any squeeks, etc. Drive them 100 miles or so to break them in. I do not use any aftermarket pastes either.

About brake pad life, 10,000 is about normal. They never lasted long on any of my MBs.

On the Honda the ORIGINAL ones from the factory lasted 70,000 miles, lol.

[benzbum]

[QUOTE=Johnson Chan]About brake pad life, 10,000 is about normal. They never lasted long on any of my MBs.QUOTE]
I disagree, unless the wagons (1984 300TDT?) are vastly different than my sedan (1985 300D-T) and brake wear is different. I think more along the lines of what Vince says - 20,000 to 30,000 miles on the front pads - is more my experience. Although minor squeaks can occur and are annoying no matter how minor, I have found that application of the Mercedes brake pad paste significantly reduces the tendency of the pads to squeak. You might find the following post from someone with a lot more experience in these matters (Marshall Booth) than me somewhat insightful:

http://mbca.cartama.net/showpost.php?p=98303&postcount=6

[Johnson Chan]

Brake pad wear also depends on how you drive and what your driving conditions are.

Stop and go city driving will wear down your brakes a lot more than freeway driving. With that said, in all 5-7 of my Benzs the average lifespan is about 10,000-15,000 miles.

[benzbum]

Brake pad wear also depends on how you drive and what your driving conditions are.
I would agree, with more emphasis on the former than the latter. If you are constantly making hard stops from high speeds, I can certainly see why you will be replacing brake pads much more frequently than normal. However, I can't see where "normal" city driving with a well-maintained and properly operating braking system would cause the pads to wear out in 10,000 miles.

Although I do very little of it, most city driving is done at maximum speeds of 25-35 miles per hour, maybe 45 on some parkways. I don't believe normal (e.g., not "panic") stops from these speeds, even if they are frequent should result in the type of wear Sysco is experiencing. I think he is right to question this and investigate the cause.

What we do know or can surmise from this post, as well as his other posts, is that Sysco lives/drives in the Boston area. From this, I think we can deduce that a fair amount of his driving is city driving. He may not get the longevity out of his pads that others who do less city driving get. However, we also know his stated driving pattern with this vehicle ("I also let the cars natural drag slow down the car as much as I can . It's to the point where I almost challange myself on how little I can actually use the brakes to slow down."). We also know that this type of brake wear is abnormal in his experience with another (albeit totally different) vehicle that we can presume is/was driven in the same manner/conditions ("I've gotten 50-70k betwwen changes when I had a Volvo 850"). I can understand why he is questioning these 10,000 mile brake pad changes in his 1984 300TDT.

I would think the questions in this case would have to be the following:

1.) Is his mechanic just suggesting to replace the pads because of squeaking or did he inspect and determine that the pads were actually worn beyond acceptable tolerances? If the former, time to get another opinion or another mechanic. If the latter, then question what is causing this accelerated wear pattern.

2.) When the pads were last replaced, were proper replacement pads used (genuine MB), were they installed using the proper MB blue-green paste and were they properly broken in? Non-MB pads may wear differently, accounting for premature wear patterns, whereas failure to use the MB-specified paste will result in squeaking issues (in my experience).

3.) Has the brake fluid always been changed in accordance with MB specifications (once a year, in the spring) using the proper MB brake fluid? If not, the system could have become contaminated causing problems with one or more of the calipers. If this is a problem, fixing it (rebuild/replace calipers and an immediate and regular brake fluid flush and refill) should result in the pads lasting a little bit (quite a bit?) longer.

4.) The car is at least 23 model years old. When was the last time the brake lines were inspected/replaced? These don't last forever and could also be causing a problem with the calipers, resulting in accelerated brake pad wear.

Again, not a mechanic, just an opinion. However, I am in Sysco's camp - 10,000 miles doesn't sound normal and he shouldn't just accept it as such.

[Sysco Kid]

Thanks for your support in my brake pad concerns.
You bring up a good thought in you questions.
Going into the spring season what other fluids should I be changing ?
I might be relying too much on my MB mechanic and really should be taking
better notes or at least keeping a complete diary . I don't have a garage full of the proper tools and am forced to frequent my mechanic but welcome your thoughts.
Yes I do live right near Boston ( 50 degrees today) but most of my driving is ouside the city in the suburbs.

Cheers
Michael :D 1984 300tdt with 106k origional miles

[Johnson Chan]

Hi Steve,

Yeah I agree with your post there are lots of variables, I guess the best way for him to find out is to do all his maintainance and repairs (i.e change brake fluid, hoses, check rotors, etc. etc.) and own the car for a couple years and it will give a better estimate of "brake pads/mile" figure.

As far as fluids, change the brake fluid, use genuine stuff and clean the reservior. The manual says to do it in the spring or fall but it doesnt really matter when its done as long as it gets done...

[dropnosky]

when was the last time you had the calipers serviced? MB used a dual piston caliper on 123s front and rear, and if one is failing to push out properly, your stopping is only coming from the single pad on the working piston on one side of the rotor. This would wear down a pad extremely fast. Ask your mechanic if this is the case.

Do NOT buy new calipers if you can avoid it (unless rusted beyond repair), this is the greatest nonsense, they will ask somewhere between 3 and 5 hundred dollars, when the rebuild kit is 50 bucks. In the rebuild kit, you will receive everything you need for the caliper, new square cut seals, new piston boots, new seals between the two sides of the caliper, and a new plate for the pushing surface of the piston. When you are done rebuilding, you essentially have done exactly what they do when they collect your core, and you basically have a brand new caliper.

What does NOT come in this kit are, new pins to hold the pads in place, new shims, new wear indicator leads, and new antirattle springs. This could be another cause of squeaking, the pins frequently wear out, and are often not replaced, as you wouldnt have to do that with modern single piston sliding calipers. Many of the components have to be ordered individually, for example, your mechanic when he orders new pads will just get the pads, shims, and wear indicator leads from MB, not the rest. He has to remember to order those other parts, and he may be tempted just to reuse what was on there, which can be done, but these items are all extremely vulnerable to rust. A pin half the diameter of a new one can allow a pad to move that much more.

I also agree that you need to check the condition of the brake fluid. Any dot 3 fluid will work fine, it is not necessary to buy exactly the same fluid from MB for 300% more money. Dot 3 is water attracting (hydroscopic) meaning that it will absorb water in the brake lines, preventing rust, and eliminating a compressible liquid, however, there is a water saturation point and upwards limit of debris that it can hold and work effectively, hence the changing of fluids schedule. You can have your mechanic test the brake fluid with a boil test. Dot 3 stands for a 300 degree boiling point, dot 4, 400, and so on.

lets say your brake fluid boils over at 150, bad, get rid of it. Remember, the engine bay is going to get hot, the lines run near exhaust and other heat generation parts, especially the calipers and pads. If you fluid boils in the line, you now have a vapor, if you have a vapor, a vapor can compress before moving the pistons (all 8), meaning no brake pedal, meaning whack, im sorry officer

[Johnson Chan]

FYI, I changed the brake fluid last fall (before the car show) using the Genuine Benz dealer stuff, and its DOT 4. It comes in a white bottle with a blue label.

You can use other DOT 4 brake fluid from any parts store, but I go with the original stuff cause thats just how I am.

Vince was there and we were bleeding the brakes, etc. He says the fluid is more of an amber/gold color compared to the valvoline dot 4 which he uses on his customers car which is more of a clear color.

Some might not care, but its just a little FYI/trivia type info for those that might be wondering...

[benzbum]

Going into the spring season what other fluids should I be changing ?1984 300tdt with 106k origional miles
Sysco:

A "Maintenance Booklet" came with these vehicles and it provides a schedule for all routine maintenance by mileage and by time. If you don't have one of these you can order it from MB by calling 1-800-FOR-MERC. You might want to confirm, but I think their latest part number for this booklet (a cheesy photocopy reproduction) is QL-6550-1477-02 and I think they'll stick you for $19.99 plus shipping and taxes.

A far better deal is the Model 123 Service Manual Library on CD. For the same $19.99 (plus shipping and taxes), you get no less than six (6) different manuals for the car: Engine Manual; Electrical Troubleshooting Manual; Maintenance Manual (this is the one that will answer your question about what service should be performed and when); Owner's Manual; Climate Control Manual; and Chassis and Body Manual. The Part Number on my CD jacket is P-2700-123-098. However, I believe they have changed the part numbers. I think the new part number is QL-6516-5610-02. It is the identical product, just different part numbers. If you choose to go this route (and I highly recommend you do), I understand from other posts on these forums that the telephone operators at 1-800-FOR-MERC sometimes can't find what you are asking for and mistakenly tell folks that the product is no longer available. If you have the part numbers you might find the going a little easier. Good luck.

[AnthroProfessor]

New calipers from MB are over $200 wholesale. I know they have rebuid kits, but does one need special tools for those things? One should not split the caliper in half by the retaining bolts, but I am not sure if the brake cylinders are going to be accessible enough.

Does one need a special lubricant for the inside of the cylinder? Simply just replace the kit parts and that's it? No catch?


What is this brake paste you guys are talking about. I never have any squeal problems when I use MB brake pads, but I don't use that MB paste either. I use a blue lubricant to put on the outside of the brake pads--the place where the Mercedes Star is printed on. I don't know if its right or wrong, so I want to learn the right thing.


As far as MB brake fluid goes, it was cheaper than the aftermarket stuff, so I have some stocked up at home. It does have a nice golden color to it.

[Don350SDL]

Brake paste: It is a type of grease that goes on the back of the pads, just like your blue grease. MB's stuff is grey-silver in color. You can buy a big jar of it (lifetime supply) or enough for one wheel in a little 'ketchup packet' size for under $2 retail.

Rebuiding the calipers is a bit more tricky. IF the bores are in good condition, it's as easy as you think. Just be sure to clean everything well and observe 'surgical' cleanliness. But, if they are pitted or scored (as they may well be - remember they stopped working right for a reason!) - then you need a cylinder hone, and if the pits are deep, they may need to be sleeved (White Post Restorations in Virginia) as the hone only goes so deep. You may need to remove a ridge in the bore end to get the new rings in there without damage, and damage occurs easily if yu aren't careful anyway.

You can use brake fluid as a lubricant, or they sell special brake lubricants for rebuilding calipers - but never ever use anything with petroleum, it'll destroy the caliper in a week. Wear rubber gloves for the entire process, brake fluid is not kind to skin.

Overall, if you don't need the car (= have plenty of time), go ahead and try rebilding them yourself. But if time is of the essence or it's your only car, get the rebuilt.

Don

[dropnosky]

you will probably need one special tool, to grip the inside of the piston and carefully remove it. Don350SDL is absolutely right, choosing to completely rebuild them is totally dependent on the condition of the surfaces. If its not working anyway, you can always inspect individually and make the choice. Even if you rebuild two, and buy two, you are still saving quite a bit of money.

[denver123]

Is replacing rear brake pads a DIY proposition? Does one need to have the special tools shown in the service manual - specifically the piston resetting pliers? (Chassis & Body Volume I, 42.4 - 160/1 F3) Would I need to bleed them? I've never done it before but an indie mechanic told me they need to be replaced, even though according to my records they are only 41k old.

Thanks in advance.

[Maxbumpo]

Is replacing rear brake pads a DIY proposition? Yes

Does one need to have the special tools shown in the service manual - specifically the piston resetting pliers? (Chassis & Body Volume I, 42.4 - 160/1 F3) No, you can pry the pads away from disc with a flat screw driver.

Would I need to bleed them? I've never done it before but an indie mechanic told me they need to be replaced, even though according to my records they are only 41k old.
Depends. I'd recommend opening the bleed screw with hose/bottle attached like one does for bleeding. Do this just prior to forcing the pads away from the disc, so that the fluid in the calipers is forced into the waste bottle vice back into the system. If you tighten the bleed screw once the pads are pushed out, you will not need to bleed the system, UNLESS you have to remove the caliper in order inspect for rebuild/replace. Correct the fluid level in the reservoir prior to driving.

[denver123]

Thank you very much for yet another serving of excellent advice.