Brake pressure regulator & Clutch master cylinder query

[swood1]

Hi all,

Just looking at my brake pressure regulator while off the vehicle.  I am just wondering if anyone can direct me to a service kit for this item?  I cannot see one on the SLS website, MB direct don't have a service kit either.  Is there a way to check if it's working off the vehicle?

Also, looking for a service kit for the clutch master cylinder for a 250SL.  I notice SLS have a 230SL but they don't have a 250SL kit. 



Regards

[waltklatt]

Swood,
Are you referring to the 9" cylinder(mounted near the rear axle) to the rear wheel disc brakes?
That's the pressure modulator to avoid having the rear wheels lock up too much during panic stops.
Try Tom Hanson at MB Classic Center.

Walter

[Kevkeller]

I had problems with mine and was able to get a replacement seal in Hungary  one time several years ago. There was a website of a restorer that did amazing work and they built a tool to test the operation of it. The website is gone now.

Supposedly the seal is the same that goes into an old Eastern Bloc truck. I made a tool to help install the seal and sent it along with an extra seal to another member here but evidently the USPO lost it.


https://www.sl113.org/forums/index.php?topic=13099.msg89173#msg89173

Kevin

[swood1]

Hi Walter, Yes that is the one.  I did find detail on the forum advising what it's for, it did baffle me for some time... I assume this item isn't on later vehicles?   

Thanks Kev, your link is helpful. I am just wondering if I could build the brake system on the bench so to speak to test it.  It's a pity that link has gone but may have a look online to see what else I can find. Can I ask where you got the diagram from your original post?  Was it from the BBB?  Shall have a look through it tonight. 


Regards

Steven

[Kevkeller]

Hi Steven,

This is what I have from the old website.  See the attachment.  I am really sorry to see it disappear as it was full of good information.  Hopefully they are still in business with a new server.

I have bought some parts to make a tester myself.  My compensator had some rust pitting in the cylinder and at some point I will bore it out and resleeve it.  One of the thousands of things I plan on doing sometime.

Kevin

[swood1]

Hi Kevin,

This is very informative.  I guess they didn't need to attach the brake booster to the circuit to confirm the system works.  Just seeing a photo showing the breakdown of the Pressure modulator/regulator is helpful.  In the photo I cannot the small rubber sleeve, can you help identify it for me? 

Steve

[Jordan]

Steve, this one looks identical to the one seen in Kevin's attachment.  Available through an Alfa parts supplier I use.  Their brake reservoirs are also the same as those used in later Pagodas.
https://classicalfa.com/products.php?product=BR012-OE-BRAKE-PRESSURE-REGULATOR-VALVE-%252d-OE

[mrfatboy]

Nothing is truly ever gone from the web if you know where to look and you are lucky 😜

Try

Web.archive.org

It partially saved that old dead link mentioned above here:

https://web.archive.org/web/20121227234023/http://weboldtimer.com/index.php?option=com_content&view=article&id=61&Itemid=72&lang=en


Let's hope it saved what you need😀

[Kevkeller]

Good to know Fat. Thank you.

Steve, I’m not sure what you’re talking about. Can you explain further?

Kevin

[swood1]

Hi all,

I shall teardown my assembly over the weekend; clean it and oil it.  But I am not 100% sure where the small rubber sleeve goes although I am sure I will find either it or remnants of it where I strip it.  FYI. The small rubber sleeve I am talking about is the one mentioned within the PDF document; on page 2.

If I'm not happy with the assembly afterwards then maybe I need to look at the one Jordon has pointed/linked to.


Steve

[Kevkeller]

Steve,

I believe you’re talking about part #3 on the diagram.  If I remember correctly that is the seal I had to purchase from the guy in Europe. The original was damaged when I had to heat the piston up to free the nut on the end.

It keeps the hydraulic fluid from leaking out the end of piston and filling up the space to the right. Does that help?

If you end up not using your pressure regulator I’ll buy it from you.

Kevin

[doitwright]

PMB Performance rebuilt my rear brake pressure regulator. I saw on their site that they rebuilt brake regulators for the Porsche 914. Having owned several 914’s in the past, I recalled that the 914 regulator looked very much like the one on my SL. ATE supplied brake components for the 914 and Mercedes of the era so I asked PMB if they would rebuild mine. It came back looking like new with new paint and zinc plated parts. I know it was under $200.

[Benz Dr.]

If you have a car with rear disc brakes you need this pressure regulator. A panic stop in wet conditions could put you into the pumpkin patch so quickly you wouldn't even know what happened. Once you start to spin it's almost impossible to recover, and you will spin if the rear wheels lock up.