[wartikars]

I own a W123 series Mercedes Benz 300D. When I was driving it from Belgaum to Pune I had to brake suddenly as the truck in the side lane suddenly came into my lane to overtake tractor in its lane. After this the brake was not working for a long time. I had to park the vehicle for some time at the side of the road. Then I was ok again. When I reached Pune I took it to the mechanic who removed air from the brake pipes. All the 4 brakes are disk brakes. I had the same problem when I was driving in the Amboli ghats from Goa to Belgaum. And the mechanic in Belgaum had to do the same thing (remove air from the brake pipes). I am unable to ascertain the root cause of the proble also at the same time I don't want to be duped by a mechanic for lack of knowledge. Please help me.

[ajmat]

Looks like you had air in the system. Check braking system for leaks. Mechanic was on the right track though

[imperial.s.a]

HI wartikar how often do you use the car first change the mastercyc assy then change the fluid then check your four wheels if they are jammed change the caliper kit your problem is over relax

[SPIKE ARRESTOR]

Dear Wartikars, a few queries :-
1.were you observing loss of brakes during hill climb or during down hill?
2.when the mechanic was doing brake bleeding did you see any air bubbles coming out, if not then air in fluid lines is not the root cause. Sometimes a phenomena called as ballooning occurs in hydraulic circuits where the hydraulic brake hoses swell up after repeated braking causing a sensation of partial brake loss or sponginess.
3.did you observe any hissing noise when you were braking during a downward decent?
4.did the brake pedal travel increase marginally (sometimes pedal feels mushy)?
5.how much pad life is left with your brakes?
If you have observed point no.3 and 4 these are symptoms of brake fade,.

Please post your reply.

[deutscheafrikar]

Originally Posted by wartikars

I I had the same problem when I was driving in the Amboli ghats from Goa to Belgaum.

Was this while going downhill? And if yes were you using the brakes constantly and not controling the speed of the vehicle down hill with your gears?

[wartikars]

Wow! Thats a phenominal amount of hwlp. Thanks to you all for coming forward to help me.

1.were you observing loss of brakes during hill climb or during down hill?
Ans: It was happening at all types of surfaces: uphill, downhill & no slant surface.

2.when the mechanic was doing brake bleeding did you see any air bubbles coming out, if not then air in fluid lines is not the root cause. Sometimes a phenomena called as ballooning occurs in hydraulic circuits where the hydraulic brake hoses swell up after repeated braking causing a sensation of partial brake loss or sponginess.
Ans: Yes, when the mechanic was doing brake bleeding there were air bubbles cominhg out. If ballooning happens which hydraulic brake hoses are to be checked (i.e. where are these hydraulic brake hoses located?)?

3.did you observe any hissing noise when you were braking during a downward decent?
Ans: There was no hissing noise.

4.did the brake pedal travel increase marginally (sometimes pedal feels mushy)?
Ans: It went all in.

5.how much pad life is left with your brakes?
Ans: How do I check this?

15th December 2009, 21:00 # (permalink[/COLOR]) deutscheafrikar

Thanks Mr. deutscheafrikar. Thats a nice suggestion I will control my vehicle on gear. But what if I am travelling on a flat surface and I have to brake suddenly due to a vehicle changing lane few metres away from me. I guess that would also a good & very valuable input from your side.

I thank you all for your inputs, help & suggestions. Do keep posting.

Gosh! Its brilliant posting queries on Team-BHP. You all rock.

[deutscheafrikar]

Wartikar,
I did not suggest that you control the car by keeping in low gears down the slope. Though actually that is the right procedure. Anyway like someone mentioned earlier maybe you need to look into the master cylinder first. It's an old car and maybe the time is up for a new Master Cylinder or perhaps you can get away with just the kit.
After that since the brake oil will also be changed you may notice improvement. The mechanic can check out the brake pads. Since you mentioned about all four wheels having disks, the pad can be checked by taking each tire out and inspectiing
The hydraulic brake hoses will connect the caliper of each wheel from the nearest metal brake pipeline, near the struts. They can get old and expand. You can replace all if they look bad
I wanted to know if you used the brakes continously going down the amboli ghat. If you do so then the disk and pads get hot. Heat is transfered form the pads to the calipers and on to the brake oil. You will find the brake pedal will go inside if the oil gets hot. Known as brake fade I think. Always drive down a hill in the same gear that you will use to drive up.
Take your car to a good mechanic or garage in your home town and get it well checked and all bad or worn parts changed. It is dangerous to drive a vehicle with brakes that don't work. It's not just your life that youre risking, but you also endanger the lives of other people on the road or near it.

[wartikars]

Sorry Deutscheafrikar,
I didn't mean that. I guess I was too short to creat wrong message in my communication.

I am not a very seasoned driver, so would always need tips to drive efficiently. I was not very well versed about the suggestion that you give.

Again apolopgies for my mis-communication. Do keep on giving me driving tips.

But you have again come up with a very nice input which is really very comprehensive. Actually this is my first car whose architecture is a bit complex as compared to the others (all Mercedes have complex architectures).

How much does a Master Cylinfer of W123 Merceds cost? And where can I buy it?

And what does a kit consist of? How much does it cost? And where can I buy it?

Disc pads where checked by the mechanic and he said that all are good. As far as the brake hose is concerened, is it of any specification?

The brake peddle was not always going it. It uesed to go in only after I had braked a bit harder.

Before any long journey and once in 6 months I take my car to the mechanic as I personally don't like endangering the lifes on this planet. This has become a habit after driving in South Africa & USA. This problem started on our return jouney. Thats the reason why I took an over night halt in Belgaum and got it repaired the whole day. I guess, I must also check for the density of the brake oil. Is it different for the Mercedes Benz cars?

Thanks again. Keep posting your inputs. Its really improving my knowledge.

[deutscheafrikar]

wartikars ,
No need to apologise. I was not offended. Anyway I think you better change the brake fluid and ask the mechanic about the mast cyl assc or mast cyl kit. Let him tell you whats needed. I suppose you will get the Kit in opera house. It will consist of rubber parts and washers, pistons and maybe springs There are many parts shops there. that fit in the master cyl.
again about the brake hoses there may be three in all an dyour mechnic will have to look and see what the condition is.
Brake fluid you will have to check what the manual or whats written on the filler cap. Accordingliy buy and put that grade.

Regards

[wartikars]

Deutscheafrikar

I will first show my car to the mechanic and then proceed accordingly.

Please let em know if you know any web site or a book/manual where I can get the information about the density & specification of the brake fluids of W123 Mercedes Benz 300D.

Warm regards.

[deutscheafrikar]

Wartikars,
In the meanwhile you can check this thread. The owner seems to be from pune too.
http://www.team-bhp.com/forum/post-1...on-repair.html

regards

[wartikars]

Thanks Deutscheafrikar! And also thanks to you all who have contributed their bit towards finding a solution for my problem.

Keep posting your inputs.

Best regards.

[wartikars]

I tried going through all the threads and also the information on the internet about the W123 series Mercedes Benz 300D. But I was not able to find the specification about the brake oil of the W123 series Mercedes Benz 300D. And how much doe the Master Cylinder & the kit cost?

[deutscheafrikar]

Get the master cylinder opened first by a good mechanic then you will know what exactly is wrong. You will have to get the cost from oper house. I don't know if pune has shops for such spares.

[wartikars]

Great! I will take the car to the mechanic. But where will I be able to find the specification about the brake oil of the W123 series Mercedes Benz 300D? Does it differ from one series to anothee i.e. W123 to W124 ........