1967 250 SL brake caliper rebuilding

[zak]

Hello all, I plan to rebuild all 4 calipers because 2 on of them the pistons are sticking and damaged the disks. I plan to replace the disks too.
My mechanic says rebuild is the way to go and is the least expensive. Plus rebuilt calipers for the rear seem to be out of stock with the big suppliers in US.
The ATE rebuild kit is under $ 20 bucks US. While the MB kit is over $ 60. Is the MB kit that superior???

How can I confirm that my car # 3019 has the ATE brakes and not Guerling brakes ?  I searched the data card and found no reference. I read in the Tech manual that Guerling was only on the 230 SL but want to confirm before I order the rebuild kits.

Is caliper rebuild a good way to go?

thanks,
jz   
 

[Tyler S]

There is an "ATE" marking in the caliper castings. It is the ATE raised lettering. My 250 sl uses ATE calipers.
If the calipers are sticking, your problem is most likely the brake hoses. The metal sheath inside corrodes, swells up, and creates enough of a restriction that the calipers wont retract. Start with the hoses first then decide if you want to tackle rebuilding the calipers. Dont forget to be sure the master cylinder is functioning/adjusted correctly.

[zak]

Interesting. Thanks for the info.
I will talk to my mechanic.

Sorry I was not clear enough. Can the ATE lettering be seen without removing the wheel?

jz

[Tyler S]

Most likely not but possibly can be seen from the inside under the car. I'm 99% sure you have ATE unless someone changed them in years past. I had the exact same problem of the left rear caliper dragging. Enough that it heated up the wheel and blistered the paint. I rebuilt the calipers only to continue to have the problem. Destroyed a brand new rotor. Only until I replaced the hoses was the issue fixed.

[WRe]

Hi,
the rebuild kits are ~20€ here, new calipers ~100€ (cheap brands) and ~200€ (premium brands e.g. ATE), ~150€ refurbished, substitutional for your old ones.
I used a rebuild kit once. It's not difficult but you need some hours because it's fiddly especially to install the dust covers. Sometimes it was really a pain to work in between the caliper.
It would be much easy when you disassemble the two parts of the caliper but you shouldn't do this (see workshop manual 42-3/6 ff *) and you need new gaskets.
Here you can see how to do it: http://w113.eu/geschlossen/Reparaturen/bremszange_ueberholen.htm .
...WRe

*  "Die beiden Hälften der Bremszange dürfen nicht voneinander getrennt werden, da die Befestigungsschrauben vom Herstellerwerk mit einem bestimmten Drehmoment angezogen sind."

[mdsalemi]

Hello all, I plan to rebuild all 4 calipers because 2 on of them the pistons are sticking and damaged the disks...Is caliper rebuild a good way to go?

Years ago, a local Foreign Auto Parts store took my nasty, frozen calipers--all four of them--and returned them rebuilt (and looking brand new might I add) in just a few days for a reasonable price; I think at the time it was about $40 each. Last year, another local place that carries a lot of OEM ATE parts offered to do the same, but prices have gone up of course... I don't know where they send them but they came back quick, inexpensive and importantly looking as good as they have performed. So, keep in mind that having your professionally rebuilt is an option you can probably source locally. In addition, there are places you can send them to that will do it as well, just do a search. With the places you send them to, an option is to have the iron casting powder coated any color you want. My choice would be the color of gray cast iron, to keep them from getting rusty-looking. That's a bit more costly...

Here's one supplier: http://goldlinebrakes.com

[zak]

Thank you gentlemen for your thoughtful replies.
I just spoke to my long time indie mechanic whose judgment I trust.
He said he has rebuilt dozens upon dozens of calipers on MBs.
He told me to order the rebuild kits, new brake lines, pads and rotors. Says he wants to paint the calipers Ferrari red but I told him silver.
I hope Peach Parts has everything in stock.
This is the same shop that is cleaning and painting the undercarriage .
He is also painting the hard top and hub caps navy blue to contrast with the Horizon Blue body that was originally factory color Papyrus White. I never figured out why- no rust or signs of any accidents.
Thank you all for your guidance.

jz   

 

[zak]

FYI
Pelican ( Peach) Parts had everything in stock, even the parking brake shoes - $305 including shipping.
Seems like a good price.

Thanks again for your help,
jz 

[mdsalemi]

I just spoke to my long time indie mechanic...he has rebuilt dozens on MBs...order the rebuild kits, new brake lines, pads and rotors.

My two cents, which you can toss away if you like.

When you send brakes out (either to a reputable brake rebuilder yourself, or through a local foreign auto parts supplier) the brake caliper is put through a very standardized rebuilding process which ensures that everything is done to specification. If all you do is brakes, you do them exceedingly well. The same holds true, as an example, for factory-rebuilt Bosch products such as alternators and starters. There's a process they go through to disassemble, and rebuilt the parts to new quality. That's not to be confused with cheap rebuilts done in some third world country with Bosch parts--I've heard there are some disasters in that realm. Lastly an engine rebuilder such as Metric Motors in the USA or Crewe Engines in UK goes through a process honed over years of engine rebuilding experience that, frankly, an independent can't touch. An "indie" may have rebuilt dozens of calipers, but that's inbetween changing oil, changing tires, flushing cooling systems, answering the phone and what have you. The rebuilding process is generally done in better controlled factory settings. Before you dismiss that, take a look at the details in the links below.

Also, consider the cost. When I was searching for restoration shops, one shop provided me a detailed example of what he did for a prior customer which included a detailed list of what it took to rebuild the starter and alternator. I can suggest that at the hourly rate of most mechanics, the cost will exceed a proper rebuilt unit. If I did the math on that rebuilt alternator and starter it was several times more costly than just buying a factory rebuilt unit. The cost of a caliper rebuild is probably in the $75 each range, inclusive. That's about the price of your parts alone, right?

I've seen several restoration projects bogged down beyond belief because the mechanic and restoration shop insisted on doing it all themselves...instead of intelligently sub-letting work where it made the most sense, usually on items such as those mentioned.

I'm sure also, that Metric Motors has many a horror story of engines being sent to them that were started by others, but given up on for one reason or another--including those started by independent mechanics that just got bogged down in too many things to focus on the proper rebuilding of an engine.

Here's a great link to a UK caliper rebuilder: http://www.brakecaliperspecialists.uk/brake-caliper-refurbishment/ They have a "do not try this at home" mantra, but do offer some guidance to those otherwise unpersuaded!

Two USA suppiers are the aforementioned Goldline Brakes, and Phoenix in Chicago. http://www.phoenixcaliper.com. Also, White Post in the USA does it with SS cylinder wall relining. http://whitepost.com/brake-sleeving-rebuilding-services/. I will have my calipers rebuilt this summer, but I'll probably just take them to All Euro, a local place that has carries all OEM ATE parts, but can send the brakes out. http://www.alleuro.com. They will come back quickly.

More on "process": http://mercedesengines.net/about-us/  and http://www.creweengines.co.uk/remanufacturing_engines_process.htm

[wjsvb ✝︎]

Another possible resource here is your local NAPA store, through their "R & R" program with A1/Cardone.  In the past, we've had hundreds of parts remanufactured through this program with excellent results.  Your NAPA store should be able to tell you whether they can do MB calipers.  Ask the mgr or the old guy behind the counter, tho.

[zak]

The dye is cast so to speak gentlemen. Parts are in and my mechanic is doing the caliper rebuilds.
I will take my chances. I dropped off the car today.

It's a 40 mile hi way drive to his shop and I enjoyed every minute. As was recommended I drove at 4500 rpms and hit 5000 on take offs and the car purred. That temp gauge stayed just above 180c the whole time. 

Thanks for all the expert advise. I appreciate it.
jz

[zak]

So the car is on the lift with wheels and tires and brakes and rotors removed.
This is the best look at the underside I have ever had with the car and I have to say that the chassis is free of any rust other then surface rust. All the vulnerable metal edges are straight, clean and rust free. All that is needed is some sanding and a new undercoat.

Another discovery I made today was the steel wheels. Three are dated 79 and one wheel is dated 80. They are the later multi holed rims. My hubcaps are also the full sized one piece type. So neither wheels nor hub caps are original.

I suspect those were changed when the car was repainted Horizon Blue changing the color from the original Papyrus White that is listed on the build card. The full dash and door sides and jambs were fully painted Horizon Blue so all the interior bits had to be fully removed to accomplish the color change. It is a good paint job. All this work could not have been done just to effect a color change I have to believe. But I look for evidence of major rust or accident damage and I can't find any. Strange. The color change was done before the car was imported from France to the US in 1984 because it is listed as blue in the 1984 paperwork.

The car is chassis # ...3019, so is an "early" late model 250 SL and was allegedly first sold in Monaco, but listed as a French market car because Monaco did not have a numbered listing in the MB country codes.

All these enjoyable mysteries to solve and thanks to the Technical Manual I get closer to the real facts.

Thanks,

jz 

[kampala]

JZ,

Maybe your Wheels (with holes) are the lightweight aluminum wheels from the 80's the look like the steel wheels.   Very desirable

https://www.sl113.org/wiki/WheelsTires/Alloys

[zak]

I wish they were aluminium, but no they are steelies.
I wonder what the weight difference is between the "old" steel wheels and the "newer" multi holed steel wheels ?
There had to be a reason they changed the steel wheel design and have all those round holes in the later design, right?
Weight savings ?

jz

[Tyler S]

Weight savings and the fact everything was changing over to rear disc brakes so cooling was most likely a factor as well. Plus the nubs for the 2 piece hubcaps were no longer needed

[zak]

Good point on the brake cooling Tyler.
The rims are stamped years 79 and 80 and are 6 inch wide models.
I guess could have come from any number of MB models back then.  What reason could anyone have to change the original steel rims with replacement steel rims ? I have no clue.

Anyway I plan to drop by and inspect the progress on her underside tomorrow. With luck I should have the car back for the weekend.

Good fun!
jz 
 

[zak]

I am happy to report that my complete brake system rebuild went seamlessly. I even ordered all the correct parts!
I picked the car up from my Indie mechanic on Saturday and have driven it over 100 miles over the weekend. The car stops straight and true and with authority.
Plus no more brake squeal!
Thanks for your advise and comments.

jz

[Sleek Lemur]

Thanks very much for the UK brake service recommendation. Going to completely go through mine and sending the calipers away certainly makes sense !