The brakes on my 82 240D auto are pretty bad.

I would say they stop OK, but with considerable pressure on the brake pedal.

Heres a list of whats been done to them:

new pads and rotors around 2 years and 20K miles ago (Cheap AutoZone crap just to get it on the road)

Fresh fluid and OEM front hoses

Checked vacuum pump operation when go through trans shifting system and all is great.

I just placed an order for some new ATE pads, new rear hoses as well as two of the "brake fluid reservoir to master cylinder seals" and am hoping this will make things better?

thoughts?

In comparison the brakes on my w116 were WAY better. That car stopped on a DIME. I would love for my 240 to stop like that.

thanks!

The w123 should stop well. I found that my w126 however stopped much easier than my w123 did with less brake pressure.

I would check that there is no brake fluid leaking into the booster. Also, boosters do occasionally go bad and need replacing. Do you feel any power assist at all?

Another option is replacing the booster with a unit from. W116/126 these are larger and provide more assist. There is a threat around sonwhere where sonobe did this. I can't remember if he used the 116 or 126 booster..

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2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

Sticking Caliper Pistons?

Along with the previousl mentioned brake Fluid inside of the Power Brake Booster what how much Vacuum do you have going to the Brake Booster?

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84 300D, 82 Volvo 244Gl Diesel

New master cylinder time. I swapped mine just because I could (didn't have terrible brakes) and it made quite the difference...

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1978 300D, 373,000km 617.912, 711.113 5 speed, 7.5mm superpump, HX30W turbo...many, many years in the making....
1977 280> 300D - 500,000km+ (to be sold...)
1984 240TD>300TD 121,000 miles, *gone*
1977 250 parts car
1988 Toyota Corona 2.0D *gone*
1975 FJ45>HJ45
1981 200>240D (to be sold...)
1999 Hyundai Lantra 1.6 *gone*
1980s Lansing Bagnall FOER 5.2 Forklift (the Mk2 engine hoist)
2001 Holden Rodeo 4JB1T 2WD

this is what I'm leaning towards...

I've checked all the calipers (one is brand new) and the vacuum going to the booster is exactly what it should be.

When you bled in new fluid, did the old fluid come out rusty? If so, some calipers may be binding or tubes might be plugged w/ rust. If you didn't bleed, then that alone is a problem since should be done every few years, unless using DOT 5 silicone fluid like me. Good brakes should be able to skid the tires, and all 4 evenly. The tires stop the car, and braking to just before skidding will stop the fastest. If your front circuit isn't working, you will only get 30% braking capability from the rears.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

The brakes definitely skid the tires in a panic stop situation. I did bleed them two years ago and don't remember the fluid being particularly nasty. I just bled them because I had replaced a caliper and the front hoses and thought it be a good thing to do.

It just feels like I have to apply more pressure than necessary for the car to come to a stop, or even for it to be held at a stop light in drive. Again, I base this off my experience with my 77 450SEL which required much less effort to come to a stop and hardly any to hold it at a stop in gear.

That's the only good thing about my 300SDL, it stops HARD.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Just a small correction. Locking up the brakes and skidding the tires is in no way a test of good or bad brakes. If anything hard braking without lockup is a much better test. Once you lock the brakes you're out of control.

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CENSORED due to not family friendly words

Let's discuss "effort" vs. "pedal travel". "Effort" is how hard you have to press the pedal (meaning you feel like it takes a lot of strength to press the pedal) and "pedal travel" means how far the pedal has to be pressed before it works (such as if it has to be pressed a decent ways before it seems to do anything).

If we're talking about "effort", you can test the booster easily enough. Work the brakes several times with the engine stopped. Note the feeling. Start the engine and work the brakes several times. Is the pedal a lot softer with greater travel? It should be if the booster is working and the vacuum pump is working.

An excessively firm brake pedal is unlikely to be the master cylinder. Your brake booster can have a torn diaphragm or leaking check valve, your vacuum pump may not be producing the vacuum you think it is, you could have seized up brake calipers, etc. Start with the basics, compare the pedal feeling with engine stopped vs engine running and get back to us.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

If this is just an effort thing, like I mentioned before, the w123 will take more pedal effort than your w116 did. It's just a matter of booster size. If you want to fix that I'd hit the junk yard and pick up an s-class booster.

I found the same thing with my 79 300D. I replaced the master cylinder, rebuilt vacuum pump, pads, and disks on all 4 corners. It stopped well, but requires a fair bit more pedal effort than other cars I'd driven, and definitely more than the w126 I owned after did.

The fellow I baught the w126 off of had had several w123's as well and mentioned the same thing about them requiring more pedal pressure to stop.

This is of course also assuming that everything is up to snuff. As mentioned check the basics first.

__________________
2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold

My 1982 240D's brakes are fantastic even when the car is fully loaded, not much pressure on the pedal is required to bring it to a halt from freeway speeds and only a gentle touch to prevent it from rolling on hilly stop signs .

Begin with a proper four wheel bleed and go from there .

Remember : simply having vacuum to the booster isn't sufficient ~ it needs to be able to HOLD the vacuum for at least 24 hours .

I too have heard many times that a W116 booster is a good upgrade .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

One of the many reasons I bought a 1981 240D for my daughters to learn to drive in are the fantastic brakes. They are exceptionally good even by today’s standards.

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1981 240D Four on the floor, Orient Red over Parchment, bought with 154,000 but it's a daily driver and up to 180,000 miles, mostly original paint and all original interior.

Have you tried a new Mazda?
Dead stop the second you begin to press the brake.

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1982 300CD Petrol/Black Leather

If the brakes are poorer than when you did the pads a couple of years ago. The pads may have become glazed. It is kind of old now but you are supposed to brake in brake pads I have seen recommended.

Or perhaps they even were of a poor composition as well when new. . By poor I mean having a low co efficient of friction factor.

The wives car and mine are not race cars. With the pads they have been selling. It is getting to the point. One set of rotors with every pad change.

I think the new pads are too hard. There are no caliper issues involved in what I am seeing. Logically if those pads are machining the rotors they probably have low grip. Requiring far More pressure.

Like the general aftermarket for car parts today. Too many producers make parts to sell rather than to do the job properly.

It seems to be all about money today more than ever. These chain parts places value their markups more than anything. I just got another set of rotors and pads delivered for the wives Toyota. She drives conservatively and a lot of highway miles. Her car should not be requiring rotors as often. Could be soft rotors I suppose.