Well... attempted to put on the new left rear caliper and the fitting cross threaded on the line... FML..... really.. FML

Now I have to get a new hose and flare wrenches. It was all going so smoothly. and I can't get the piece of **** hose locally

Sorry to hear about your luck on this one. I thought you were asking for the size of die on a flare nut tool to build new steel lines and thread type/pitch for some reason. I see now, you just wanted the size of wrench for the fittings. All the Mercs I've encountered so far (w126, w123) chassis have what Vstech says... 14mm on the hose and 11mm on the steel line.

I found some hoses originally at a small shop that did work on German imports. I used to get all my parts from him....great guys...gave me lots of advice on various repairs. I paid 90 dollars for the set of 2 until I found out (from here) I could get them way cheaper, so I took the expensive ones back and got a refund to get my set of 4 cheaper ones with change to spare. I paid 45 bucks for all 4 hoses. The 90 dollar set/2 from the Mercedes mechanic were Beck Arnley... took them back and got Beck Arnley from Acklands for 22 bucks/set.

If you type in those part numbers I gave you....those hoses are listed for many...many different Mercedes cars. I find it hard to believe they can't get those hoses in stock where you are compared to the lowly populated sh**hole where I am at. Aside from the small mechanic shop, I got one new set from Acklands and they were in stock. The other set had to come from a city in the next province but I had them the next day.

What would happen if you asked the suppliers for the part numbers instead of giving them your specific vehicle information? Perhaps they have them for another year/model but their software does'nt cross-reference?

I have the Harbor Freight set and they worked a treat, but my fittings really weren't all that tight, much to my surprise. I'm still not used to living in a place where 30-year-old cars don't have every fitting welded together with rust.

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1981 Mercedes 300TD, 1994 Honda Civic Del Sol
http://mefi.us/images/fuelly/smallsig-us/67195.pnghttp://mefi.us/images/fuelly/smallsig-us/103885.png

Just a note. I believe all the rear calipers mentioned above will interchange. The wagon rear calipers use the same pads but have slightly larger diameter pistons so you don't want to mix them in with the calipers from sedans. I am pretty certain all the brake hoses will be the same fitting size.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

So I couldn't get the used line from the junkyard, the fittings were stuck together and I rounded them off. I was able to remove the left rear hose like I had wanted. I have two new hoses coming tomorrow. Two used calipers and two new hoses brings it ot $50 plus the $35 for my flare wrenches. Sears said my $10 off coupon was expired... Customer service will be hearing from me.

Anyways... I spun the wheels with the calipers off and didn't hear anything dragging. I do hope its not the master cylinder. I've never bench bled one of those and I do not want to deal with the flare nuts.

I also hope I didn't screw up the threads on the caliper. I believe the original calipers are ATE's and the replacements I have are ATE's so I might be ok if I just leave the original on the left rear.

So it is true about pistons being different sizes for some calipers that otherwise look the same and bolt up the same. I wonder if there is a part number reference for this?

Sedan/coupe rear caipers-123-420-05-83
w126 300SD------123-420-05-83
w126 420 sel------123-420-05-83

wagon rear calipers-123-420-12-83

t walgamuth is correct...A quick look at the part numbers on here reveals that there is a difference in the part numbers. It appears the wagon rear calipers are different.....is this the number that is stamped on the caliper itself or is there another number to differentiate?

If they bolt up, why worry if the pistons are a different size? And I started on my front brakes today and had some siezed pistons in the calipers so I ordered new ones (bendix) from napa, which is our only parts store on this island. Should be here tomorrow. Already got a new master, so after work tomorrow, I'll dive in. Glad to see I'm not the only one frustrated with old brakes tonight!

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'85 300 TD wagon. Euro spec. 215,000 miles, real beater (for now). '59 f350 with cummins 6at, 54 gmc flatbed with cummins 6at, '92 f350 service truck with 7.3 NA IDI and 5 spd man tran, Grumman Aluminum stepvan with 6.2 (cabinet hauler) I like diesels.....

Is there a proportioning valve on these or is this different on the master cylinders?

Looks like all w123 cars...coupe, wagon and sedan share the same part numbers...but the 300sd has a different part number m/c.

Then the 420 sel gassers yet have another different number for the master cylinder.

Makes me wonder if the 300sd master cylinder should be used in a "big brake upgrade" application rather than the w123 m/c?

What are the differences in the master cylinders...is the SD bigger for the larger chassis?

Do the SD's have vented front rotors like the 420 sel?

I wonder if a person might want to get some rebuild kits to do the calipers that come off the car as back ups while you drive on the used one that are inbound.

I would like to do this with the old rear calipers laying around here for some back ups. I guess the rear caliper kit would have to be specific to the piston size. The rebuild kits on here reflect the differences in part numbers for the rebuild kits for each model....cool, accurate.

You could get crazy and powder coat the caliper bodies Ferrari red. A guy was telling me you can powder coat small parts at home with some sort of kit. I wonder how it turns out?

I'm going to rebuild the old calipers.

Is there a caliper rebuild link on here?