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1993 300E 2.8
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Discussion Starter #1
When I attach the pressure bleeder to the brake fluid reservoir in my '93 300E (W124), the pressure wouldn't hold. I could get it up to close to 8 psi and it quickly loses it. Further looking, I could feel on my finger, air going out from under one or both of the protective caps found on the reservoir (p/n 001 431 26 87). Is this normal? or are they supposed to be air tight?
What are under the two black protective caps and how to remove them...just pull it up?

Thanks for any information on this as I don't want to break one of those and make it worse.

Thanks in advance.
 

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2008 E350 4M, 2016 Audi Allroad, 2019 Audi Q5
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5,445 Posts
It should hold pressure....Looks like you are on the right track.
 

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1993 300E 2.8
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329 Posts
Discussion Starter #3
Thanks ps2cho. I found that these protective caps on my car have cracks (see pics - the two circular black caps) and so I will replace them.

Anyone know if they just pull up and out? Don't want to do more damage.

Also this morning I found a puddle under the rear end and when looked under, it seems the brake line going to rear passenger side brake (line going across by the gas tank) has developed a leak (see pic). It must have happened yesterday when I added some brake fluid to top and pressurized the Motive power bleeder. (This actually solves my mystery of the oil level in the reservoir going down when I looked later.)

Replace just this section of the brake line? Is the brake line repair a DIY? Thanks again for the help.
 

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2008 E350 4M, 2016 Audi Allroad, 2019 Audi Q5
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I think replacement of those lines is gonna be a PIA....

Either way that is not good because it was probably leaking out every time you pressed the brakes and increased pressure in the lines. Not safe! Once you resolve that leak and bleed the system free of air I bet your braking will improve.
 

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1993 300E 2.8
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Discussion Starter #5
Yeah I'm glad I found it when the car is on jackstands. I started this project because the brakes were soft -- so now I know.

I think I'm going to tackle the lines, all of it. I have to do some searching on DIYs first. Any warnings/tricks from the experienced are welcome. This forum has always been very helpful. Thanks.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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Be sure and get the appropriate metric flare nut wrenches and possibly some crow's foot wrenches for really tight places. If you can order MB lines pre-bent and metric, that will help you a lot. But tubing benders are pretty cheap and you can buy some tubing lengths to practice on. If you're going that route, you'll also want to get a double flaring tool-brake lines use a double flare instead of the simple flare. It just means that the lip of the flare is substantially thicker so the tubing can't pull out under any circumstances. If you don't have one, you'll need a tubing cutter and internal reamer (usually built into the cutter) as well-again, these are out there on the cheap.....doesn't have to be Snap-on for this one job.

Kevin
 

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W124
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An effective fix would be to find how far upstream of the break you still have solid line then cut it there and splice in a new line. Buy a double flaring tool mentioned above and a replacement line that's got a bubble flare for the end that you will remove from that union in the photo, then put a double flare on the existing line at a spot where the existing line is sold and add a union (double flaring the opposite end of the new line you installed in the union so it fits solidly into the new union). Make sense?
 

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'89 300TE, '79 450SL, '01 ML320
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I went thru this mess earlier this year on on my 300D, noticed a small puddle of diesel under
the car. Stopped at an auto parts store on my way to the shop and grabbed a length of
1/4" line, some hose, and a couple clamps. Figured I'd just splice it in and be on my way,
yeah right! Put it up on the rack and removed the body clamp at the leak...

I'll leave out the parts where every thing I touched disinigrated, or the walk a half mile to
the parts store twice for assorted lengths of line and exchanging double flare lines for
bubble flare lines :(
And skip to the part where eight hours later my W123 has all new brake and fuel lines.
A bear of a job, and will try your patience on several levels, but you can do it.

Moral of the story, if there is one, get the right lines with European ISO 'bubble' flares and prepare yourself
for replacing all the lines. Rust really likes to form under these body clamps.
Also if you have an SAE double flare tool, you 'might' be able to get by with it.
The first part of forming the double results in a bubble, my tool would not grip the metric
line tight enough. I can't say for sure if the dimension of the bubble is the same.


Fish

PS I also left out the part where my wife laughed her ass of at my diesel/brake fluid encrusted hair doo :)
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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Given the amount of corrosion obviously present in the pic, I think it's a really BAD idea to cut & patch any of the lines. Any line that has a leak and lost some integrity, should be replaced in its entirety. Brake systems are items where the mighty weekend warrior shouldn't be trying to save a buck or save some time.

Kevin
 

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1993 MB 500E, 1965 MB 220b
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77 Posts
Brake Line Replacement Solution

If you need to replace brake lines, save yourself a lot of aggravation by ordering a pre-made kit from PartsAmerican Auto Parts of Minnesota:

Brake line kit BMW,Mercedes 1992 1993 1994 1995 1996 - eBay (item 300496399717 end time Dec-23-10 07:46:22 PST)

For about $55 delivered, you get 16 lines & 4 unions (enough to do about 2 cars). Each line has the special bubble flare & nut required for our cars.

I replaced lines on one of my cars using this kit. The lines are very easy to work with & provided me with great results. In a pinch, you can even get by without a tube bender (although I recommend using one for intricate bends). The lines are well-made & highly malleable; if you don't like your bend, the lines are easy to restraighten & try over again (you'd have to be trying real hard inorder to kink them!).

Don't compromise your safety. If one line has gone, its the messenger telling you the rest are soon to follow. Get the kit & get back on the road! Kits are available for about any year Benz.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,383 Posts
If you need to replace brake lines, save yourself a lot of aggravation by ordering a pre-made kit from PartsAmerican Auto Parts of Minnesota:

Brake line kit BMW,Mercedes 1992 1993 1994 1995 1996 - eBay (item 300496399717 end time Dec-23-10 07:46:22 PST)

For about $55 delivered, you get 16 lines & 4 unions (enough to do about 2 cars). Each line has the special bubble flare & nut required for our cars.

I replaced lines on one of my cars using this kit. The lines are very easy to work with & provided me with great results. In a pinch, you can even get by without a tube bender (although I recommend using one for intricate bends). The lines are well-made & highly malleable; if you don't like your bend, the lines are easy to restraighten & try over again (you'd have to be trying real hard inorder to kink them!).

Don't compromise your safety. If one line has gone, its the messenger telling you the rest are soon to follow. Get the kit & get back on the road! Kits are available for about any year Benz.
This is excellent advice, as I didn't know the kits were so inexpensive. I can't see any other way to go for safety and value.:thumbsup:

Kevin
 

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1993 300E 2.8
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Discussion Starter #12
Thanks for all the suggestions/ideas -- yes I will replace all lines given I see rust around clamps/joints.

Lines from the dealer comes to around $150 delivered. I am leaning towards the kit from DerFuror's link above rather than doing all the work from scratch. How do they compare to the dealer lines quality wise?

While at it, I will replace the brake hoses as well (they look fine but I don't recall them ever getting replaced.)

Can air get in the system while replacing these..any order of lines to follow? I know I have to bleed the brakes afterwards and will that take care of everything ?

Thanks again.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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10,383 Posts
Yes, you'll get copious amounts of air into your system replacing the lines. You have a power bleeder as pictured in your posts-that's what you want to use to finish bleeding your system after all lines are replaced. You may have a bleeder nipple on the ABS pump as well. Follow the instruction cached here for power bleeding the entire system.

Kevin
 

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W124
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From the looks of the picture the only place the line is leaking is where it has been retained in the clamp. This is very common and not the sign of weak lines. The 123 fuel lines are notorious for failing at the very spot where they are being retained. I think its a place were moisture builds and erodes the line. The rust in those shots is surface rust IMO. But if you can get the whole line in one piece that's great.
 

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'92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
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"The rust in those shots is surface rust IMO. But if you can get the whole line in one piece that's great."

No....I live in a climate with what we call 'surface rust'. What's pictured is corrosion. We only see rust like that if it's fished out of a river.

Kevin
 

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1993 300E 2.8
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Discussion Starter #16
After reading these...I thought of taking a closer look. It seems all the lines going to the fronts and the ones under the hood are in good shape. I don't think I need to replace those. Then the line which goes to the back from under, goes through an adapter fitting. This area looks rusty but seem to be holding up well. Then the line goes to a 3-way distributor in the back. This line from front o back also seem to be ok with a bit of surface rust at the connection to the distributor. The lines from the distributor to the two rears definitely has corrosion at that junction. Also all four brake hoses seem to be in good shape.

So my thinking is to replace the two rear lines with dealer parts (~$30+shipping)... unless I am missing something just doing a visual inspection??? Wondering if I should also replace the 3-way distributor and the adapter fitting or are they rather solid compared to the line.

I took some pictures for any comments. Thanks again.
 

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Discussion Starter #17

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1993 300E 2.8
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Discussion Starter #19
Fish, thanks for confirming. I'm ordering the left and right rear lines from Advance Auto and bend them myself. ( I wasn't sure whether dealer lines are pre-bent or not and they cost more than 3x these) . As long as I don't have to do the flares, I should be ok and hope it not be as eventful as when you did them.... also I will wear a hat...

FYI for anyone: Rear Left 20" and Rear Right 30" long for my '93 300E 2.8.
 

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'89 300TE, '79 450SL, '01 ML320
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A hat, why didn't I think of that :)
Just one more tip, those fittings are pretty rusty, just cut the lines at the fittings so you
can get on them with a 6 point socket. They may round of anyway but it's worth a shot,
saves the agravation of dealing with visegrips. Good Luck!


Fish
 
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