Author Topic: Brakes get hot as hell (Read 4827 times)

free2keun · « **on:** June 29, 2018, 11:47:23 »

Since 3 weeks, I drive my W113-1963. There is always a problem with the brakes. After 10 km, both front brakes get hot as hell and the wheels get totally stuck. I asked several garagist what could be the problem. they gave all different solutions. I took a look on this forum, but I didn't found yet a solution to solve the problem
These are the things what I have already checked..
The brakes are Girling. I checked the brake cylinder pistons. When the bleeder valve is open, then the cylinders come very easily in and out.
I put new brake oil from reservoir to caliper.
The brake hoses are totally new.
The brake booster is checked, and work well.
I put the eccentrically bolt in all ways, but the problem still comes back.
I can not put the brake pads in when the bleeder valve is closed ! So this is the problem I guess. Where do I have to look ?

Cees Klumper · « **Reply #1 on:** June 29, 2018, 12:55:11 »

I believe there is pressure regulating valve underneath the car that regulates how much pressure goes to the front vs the rear wheels. Perhaps that is your culprit. Otherwise I would have said definitely the dront brake hoses but you already replaced those. Or perhaps one of your hard brake lines is damaged/constricted.

free2keun · « **Reply #2 on:** June 29, 2018, 13:10:15 »

Thanks Cees for your help !

The thing is that both brakes have the same problem, the same time

Tyler S · « **Reply #3 on:** June 29, 2018, 13:26:33 »

When the Brakes lock up, crack loose the line fitting at the master cylinder. If pressure escapes and the brakes free up, focus on the master cylinder. there may also be an issue with the brake booster not fully retracting. Remove the booster vacuum line and again see if the brakes free up.
Have the booster or master cylinder been replaced? Some have had issues with the rod length.

ejboyd5 · « **Reply #4 on:** June 30, 2018, 11:20:08 »

Disconnect and plug the vacuum hose to the master cylinder. If the problem goes away you have identified the master cylinder as the culprit.

free2keun · « **Reply #5 on:** July 01, 2018, 17:54:54 »

Thank you ejboyd5 for your help.
So I have to disconnect the vacuum hose from the brake booster.. and where do I have to connect the hose to.. ? to the master cylinder.. ? Can you show it me with a picture ?
today i drove 5km, and then the brakes were stuck ! so bad, it was like I had a trailer of 2000kg behind :-( . So i drove back home in second gear at 30 km/h
I really didn't use the brakes too much, maybe 3 times.

ejboyd5 · « **Reply #6 on:** July 01, 2018, 22:07:33 »

Do not connect the vacuum line to anything, simply plug the end where it attached to the master cylinder so as to preserve engine vacuum. If the brakes still lock with the vacuum source disconnected, the next logical step is to check the "off" position (length) of the actuating rod which may be too long and keeping the brakes applied.

UJJ · « **Reply #7 on:** July 02, 2018, 14:51:29 »

I have found that a lot of times the brake hoses swell in the inside, not letting the pressure off.
However, it is unlikely that this happens to both sides at the same time.
But I thought I mention it. Urban

neelyrc · « **Reply #8 on:** July 02, 2018, 20:15:14 »

Urban, I had this problem once as well, but I understood from the initial post above that the brake hoses are totally new. I was told many years ago to only use MB brake fluid to prevent this internal deterioration of the hoses. I followed this advise but probably did not renew the fluid frequently enough.

Benz Dr. · « **Reply #9 on:** July 02, 2018, 21:14:38 »

If you can dive away and the car roles freely it isn't brake hoses. If, after applying the brakes a few times the car is eventually unable to move, that's a problem with brake pedal free play at the push pin.
Set the eccentric to point towards the brake booster. If they still lock up then you may have a problem with an incompatible master cylinder and brake booster. The round faced late booster should only be used with the later 280SL master. I've had problems like this before where nothing I did would solve the problem until I changed the MC.

The pressure release port at the back of the MC must remain open when the brakes are released. If not, the brakes will drag a bit causing heat which will make the brake fluid expand casing the brakes to eventually lock up. Sound familiar?

A Dalton · « **Reply #10 on:** July 02, 2018, 22:37:12 »

https://www.sls-hh-shop.de/main/en/mercedes-230-280sl-w113-/42-brakes/43-mastercylinder

Lube area where part 47 is....they bind up , not allowing full return of that transfer lever.

This is the pivot end of the lever with the eccentric adjuster.

Benz Dr. · « **Reply #11 on:** July 03, 2018, 05:15:51 »

Yes, that area can seize up but both ends of the lever have plastic bushings so that is not supposed to happen. Good call! I did see that once or twice - not common but not impossible either.

free2keun · « **Reply #12 on:** July 03, 2018, 11:34:36 »

Thank You Dr. Benz for your knowledge. In annex you will find a picture of the present brake booster and the master cylinder. Maybe you can see if there is an anomalie (for a 230 SL '63) ?
Don't look at the water reservoir, this comes from an old Honda Goldwing, but it works.. :-) . The brake oil reservoir is also something that not belong to the origin...

Thanks also to the other people that have given answers to this problem

Benz Dr. · « **Reply #13 on:** July 03, 2018, 14:34:53 »

The booster is 230SL type but the master may not be.

free2keun · « **Reply #14 on:** July 03, 2018, 15:06:45 »

Yesterday, there was Japan - Belgium (we won against the Japs

)
tonight i will make a ride without the vacuum hose and see if the problem stays.

the only thing that i have to do is close the vacuum hose so there can't get air in the motor block..

Benz Dr. · « **Reply #15 on:** July 03, 2018, 22:50:42 »

Be very aware that you will have next to no brakes without the booster working. Make your drive in an area that's not busy and be very careful.

free2keun · « **Reply #16 on:** July 04, 2018, 03:45:38 »

So, like Tyler S. and ejbojd 5 said, do a test ride without the vacuum hose from the brake booster and see..

Again disappointed results. I have to focus on the master cylinder as like Benz Dr. said.

What is the best thing I do now ? Open the master cylinder and clean it with air pressure or buy a new one ?

Tonight I put here a better picture of the master cylinder to see if it is an original one.

WRe · « **Reply #17 on:** July 04, 2018, 06:32:27 »

Hi,
when a mastercylinder fails it's often because of the internal rubber seals. You can use a repairkit (cheap with rubbers only, ~70€ plus springs and pistons) or buy a new one (Ate ~90-140€ depends on model). I would buy a new one.
...WRe

free2keun · « **Reply #18 on:** July 04, 2018, 09:00:33 »

So, like Tyler S. and ejbojd 5 said, do a test ride without the vacuum hose from the brake booster and see..

Again disappointed results. I have to focus on the master cylinder as like Benz Dr. said.

What is the best thing I do now ? Open the master cylinder and clean it with air pressure or buy a new one ?

Tonight I put here a better picture of the master cylinder to see if it is an original one.

free2keun · « **Reply #19 on:** July 04, 2018, 09:05:47 »

Hello WRe. Thanks for your advice !

From what site do you get these prices ? The prices by SLS are a bit higher.

WRe · « **Reply #20 on:** July 04, 2018, 10:51:16 »

Hi,
see here: https://www.daparto.de/Ersatzteile/Mercedes-Benz-SL-Pagode-W113/2-1211-?kbaTypeId=886#category-1456-1457.
...WRe

free2keun · « **Reply #21 on:** July 04, 2018, 17:49:50 »

Herr WRe. Danke schön für die link

Today, I did a last test about the brake failure. I open the outport on the master cylinder to see if there is any congestion. When I open the brakes cylinders, the oil was running free..

Once closed, the brake cylinders couldn't not be opened.

free2keun · « **Reply #22 on:** July 05, 2018, 20:26:53 »

Dear friends, first I will thank you all for your help !

When I was watching for new components, I saw that the brake cylinder that is mounted on my 230SL does not agree with pictures I see on the internet. I took some pictures of the present brake cylinder and put some explanation on it. Is my brake cylinder an original piece ? My 230SL is a very very early model, from november '63.

I want to finish with this brake problem.

Sleek Lemur · « **Reply #23 on:** July 12, 2018, 16:30:43 »

Sounds similar to my issues. Check out the replies from our ever-helpful experts !

https://www.sl113.org/forums/index.php?topic=27788.0

News:

Author Topic: Brakes get hot as hell (Read 4827 times)

A Dalton

Sleek Lemur