Since its founding in late 2008, 500Eboard has become the leading resource on the Internet for all things related to the Mercedes-Benz 500E and E500. In recent years, we have also expanded to include the 400E and E420 models, which are directly related to the 500E/E500.
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There are different boosters for 1990's vintage MB's, both single and dual chamber. The dual-chamber provide additional pedal assist ("boost") vs single. There are various levels of boost. See chart at PDF page #6 at this link, the "boost factor" shows the relative difference.
Boost factor only affects pedal effort, which is NOT the same as braking power. Too much assist means the pedal is very sensitive / touchy, which is annoying. Too little assist and the pedal requires a lot of force / leg muscle to get the stopping power you want. To get more braking power (reduced stopping distances) you need larger brake rotors/calipers, and/or different pad compound, and/or stickier tires.
Click the link below for my journey down the booster swap road from almost 15 years ago. Read the whole thread, it starts out all sunshine and lollipops, but storm clouds appear in post #2:
TLDR: Pedal feel is highly subjective, and what one person thinks is great, another may not like at all. Pad compound can seriously affect pedal feel as well. Bigger is not always better, as I learned the hard way; I had to "downgrade" to a different setup after my big MC+booster turned out to be un-modulateable (hmmm, is that even a word?) during trail braking.
E-Class (W124) - W124 brake booster & master cylinder upgrade - Hi everyone, As you may (or may not) recall, I installed early 500E brakes on my 1987 300D earlier this year (300mm front (http://www.w124performance.com/images/W124_brakes/300mm_front2.jpg), 278mm rear...
There are different boosters for 1990's vintage MB's, both single and dual chamber. The dual-chamber provide additional pedal assist ("boost") vs single. There are various levels of boost. See chart at PDF page #6 at this link, the "boost factor" shows the relative difference.
Boost factor only affects pedal effort, which is NOT the same as braking power. Too much assist means the pedal is very sensitive / touchy, which is annoying. Too little assist and the pedal requires a lot of force / leg muscle to get the stopping power you want. To get more braking power (reduced stopping distances) you need larger brake rotors/calipers, and/or different pad compound, and/or stickier tires.
Click the link below for my journey down the booster swap road from almost 15 years ago. Read the whole thread, it starts out all sunshine and lollipops, but storm clouds appear in post #2:
TLDR: Pedal feel is highly subjective, and what one person thinks is great, another may not like at all. Pad compound can seriously affect pedal feel as well. Bigger is not always better, as I learned the hard way; I had to "downgrade" to a different setup after my big MC+booster turned out to be un-modulateable (hmmm, is that even a word?) during trail braking.
E-Class (W124) - W124 brake booster & master cylinder upgrade - Hi everyone, As you may (or may not) recall, I installed early 500E brakes on my 1987 300D earlier this year (300mm front (http://www.w124performance.com/images/W124_brakes/300mm_front2.jpg), 278mm rear...
Thanks @gsxr
really appreciate the information. That is exactly what i have concluded. However there are write ups that state dual diaphram boosters provide more brake fluid pressure to disc brakes. especially big brake upgrades.
Power brake boosters offer lower pedal effort and better braking characteristics, but which one is right for your hot rod, muscle car, or truck? We take the guesswork out of that question with our latest buyer's guide.
Thanks @gsxr
really appreciate the information. That is exactly what i have concluded. However there are write ups that state dual diaphram boosters provide more brake fluid pressure to disc brakes. especially big brake upgrades.
More pressure isn't always a good thing. As noted in my previous post, too much pressure (for a given amount of pedal effort) results in a super-touchy pedal that is basically unusable for normal driving. You only want/need a larger booster, with more assist, if you find it requires too much pedal pressure for the desired braking power. If it feels like there's no power assist, yeah, you may need a bigger booster.
"Single diaphragm brake boosters are commonly used for four-wheel drum or front disc/rear drum brake system configurations. Since drum brakes require a lower fluid pressure to actuate, the single diaphragm provides enough assistance. When upgrading to four-wheel disc brakes a dual diaphragm brake booster is recommended due to the higher fluid pressures required to move the multiple disc brake caliper pistons found at all four corners of the vehicle."
All modern MB's have 4-wheel discs and few of those have a single-diaphragm booster.
There are different boosters for 1990's vintage MB's, both single and dual chamber. The dual-chamber provide additional pedal assist ("boost") vs single. There are various levels of boost. See chart at PDF page #6 at this link, the "boost factor" shows the relative difference.
Boost factor only affects pedal effort, which is NOT the same as braking power. Too much assist means the pedal is very sensitive / touchy, which is annoying. Too little assist and the pedal requires a lot of force / leg muscle to get the stopping power you want. To get more braking power (reduced stopping distances) you need larger brake rotors/calipers, and/or different pad compound, and/or stickier tires.
Click the link below for my journey down the booster swap road from almost 15 years ago. Read the whole thread, it starts out all sunshine and lollipops, but storm clouds appear in post #2:
TLDR: Pedal feel is highly subjective, and what one person thinks is great, another may not like at all. Pad compound can seriously affect pedal feel as well. Bigger is not always better, as I learned the hard way; I had to "downgrade" to a different setup after my big MC+booster turned out to be un-modulateable (hmmm, is that even a word?) during trail braking.
E-Class (W124) - W124 brake booster & master cylinder upgrade - Hi everyone, As you may (or may not) recall, I installed early 500E brakes on my 1987 300D earlier this year (300mm front (http://www.w124performance.com/images/W124_brakes/300mm_front2.jpg), 278mm rear...
watching with popcorn, but curious if there is an E500E definitive fix for the noisey result from stepping on the brake pedal? (audible annoyance only not a braking problem)
Got it. You upgraded 2 steps, from the single-diaphragm 10" with 3.85 boost factor used on most 6-cyl 124 and most W202, to the dual-diaphragm 8/9" with 5.60 boost, used on the 400E/500E and most R129's to 1997. Should be a pretty big difference.
Got it. You upgraded 2 steps, from the single-diaphragm 10" with 3.85 boost factor used on most 6-cyl 124 and most W202, to the dual-diaphragm 8/9" with 5.60 boost, used on the 400E/500E and most R129's to 1997. Should be a pretty big difference.
Yes. i retained the stock C36 master cylinder. not sure what the difference of master cylinders. physically, they looked very similar so my mechanic just decided to keep the stock one.
Got it. You upgraded 2 steps, from the single-diaphragm 10" with 3.85 boost factor used on most 6-cyl 124 and most W202, to the dual-diaphragm 8/9" with 5.60 boost, used on the 400E/500E and most R129's to 1997. Should be a pretty big difference.
First of all, I wanted to thank you for your great contribution to the community.
Do you happen to have any information (diameter / boost factor, etc.) about part number A0044302730, please?
I am looking to upgrade the brake booster and master cylinder on my W124.
For the master cylinder, I am considering using A0044307501.
For the brake booster, I initially planned to use A0044302230 or A0044306530, but they are very difficult to find in my area.
I was therefore thinking about switching to A0044302730, but I’m not sure what the differences are.
First of all, I wanted to thank you for your great contribution to the community.
Do you happen to have any information (diameter / boost factor, etc.) about part number A0044302730, please?
I am looking to upgrade the brake booster and master cylinder on my W124.
For the master cylinder, I am considering using A0044307501.
For the brake booster, I initially planned to use A0044302230 or A0044306530, but they are very difficult to find in my area.
I was therefore thinking about switching to A0044302730, but I’m not sure what the differences are.
What year / model is your 124? Be careful with the upgrades, the wrong mix of parts can result in sub-optimal braking performance.
A0044302730 does not exist in the EPC but appears to be used on 6-cyl 140 and most R129 (except V12 and late R129). If so, it's the same size / boost factor as the 400E/500E booster. A0044306530 is the 400E/500E booster.
I'm not sure about the differences between the various boosters, but the location of the vacuum port may vary, which could cause problems.
If you haven't seen my brake spreadsheet before, click here, check out the page with booster specs. Part numbers are not on there... I need to try and add those for reference. So, it takes some work to figure out what part numbers are used on which chassis/engine combination.
What year / model is your 124? Be careful with the upgrades, the wrong mix of parts can result in sub-optimal braking performance.
A0044302730 does not exist in the EPC but appears to be used on 6-cyl 140 and most R129 (except V12 and late R129). If so, it's the same size / boost factor as the 400E/500E booster. A0044306530 is the 400E/500E booster.
I'm not sure about the differences between the various boosters, but the location of the vacuum port may vary, which could cause problems.
If you haven't seen my brake spreadsheet before, click here, check out the page with booster specs. Part numbers are not on there... I need to try and add those for reference. So, it takes some work to figure out what part numbers are used on which chassis/engine combination.
What year / model is your 124? Be careful with the upgrades, the wrong mix of parts can result in sub-optimal braking performance.
A0044302730 does not exist in the EPC but appears to be used on 6-cyl 140 and most R129 (except V12 and late R129). If so, it's the same size / boost factor as the 400E/500E booster. A0044306530 is the 400E/500E booster.
I'm not sure about the differences between the various boosters, but the location of the vacuum port may vary, which could cause problems.
If you haven't seen my brake spreadsheet before, click here, check out the page with booster specs. Part numbers are not on there... I need to try and add those for reference. So, it takes some work to figure out what part numbers are used on which chassis/engine combination.
I have a 1991 W124 250 Turbo Diesel (124.128) that has been swapped with an OM605 turbo diesel engine. Of course, I used your website, aka the W124 Bible.
For the braking system, I made the following modifications: Front: ATE 320×30 0014200083 / 0014200183 Rear: ATE 278×9 1294200283 / 1294200383
I tried to replicate the U.S.-spec E500 setup, which normally uses 278×24 discs on rear, but the calipers were difficult to find and very expensive. I believe that since the disc diameter and piston sizes are the same, there should not be any brake balance issues; however, brake endurance will obviously not be the same, and there is a risk of disc warping. If that turns out to be the case, I will try to source 278×24 discs or possibly 300×22.
For the master cylinder, I am planning to use a new A0044307501, most likely from ATE.
Regarding the brake booster, I have just found an A0044306530. I will see whether the braking is too sensitive with it; otherwise, I will do as you did and try to find a limousine brake booster, A0044300030. Do you know whether TRW is a good brand for brake boosters?
I have a 1991 W124 250 Turbo Diesel (124.128) that has been swapped with an OM605 turbo diesel engine. Of course, I used your website, aka the W124 Bible.
For the braking system, I made the following modifications: Front: ATE 320×30 0014200083 / 0014200183 Rear: ATE 278×9 1294200283 / 1294200383
I tried to replicate the U.S.-spec E500 setup, which normally uses 278×24 discs on rear, but the calipers were difficult to find and very expensive. I believe that since the disc diameter and piston sizes are the same, there should not be any brake balance issues; however, brake endurance will obviously not be the same, and there is a risk of disc warping. If that turns out to be the case, I will try to source 278×24 discs or possibly 300×22.
Nice upgrade there! The non-vented rears should provide the same brake bias as a USA-spec E500, just with a bit less fade resistance. The 320mm fronts are a massive improvement on the lightweight 124.128 chassis.
For the master cylinder, I am planning to use a new A0044307501, most likely from ATE.
Regarding the brake booster, I have just found an A0044306530. I will see whether the braking is too sensitive with it; otherwise, I will do as you did and try to find a limousine brake booster, A0044300030.
I've always obtained used brake boosters. I don't know if TRW makes new aftermarket boosters, but TRW is generally decent stuff (except for their cheap LCA's, but that's a different discussion).
We wanted to let you know about a new resource that is now available to all 500Eboard members. This is a comprehensive database of all US-market (and soon to include Canadian-market) 500E and E500 models delivered for the 1992 through 1994 model years.
Data for this resource has been compiled continuously since mid-2003, and much of this information is seeing the light of day for the very first time ever. This new resource will allow you to utilize 500Eboard research and resources to track specific cars, their sale history, documented modifications, and other information that has surfaced over the years.
We are also providing analytics about the cars' production. This means that if you are curious as to how many "Signal Red" cars were produced for the US market with a black interior, specifically in Model Year 1993, you can now easily find this information. You can also find aggregated information -- for example, how many "Black Pearl" cars were imported into the US over the three-year span.
You can always find and enjoy this resource by clicking here (bookmark the site for easy reference!), or by going to the “500Eboard Registry and VIN Database” sub-forum below. You can also find a VIN Database button at the top of your screen, for easy access.
We hope you enjoy this resource. A LOT of blood, sweat and tears over nearly 23 years have gone into its creation.
Cheers,
500Eboard Management
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