sl 300 Brake and start problem

[Paulmerc]

Hi everyone hope your keeping well, I have an 1989 sl 300, with two problems, I don,t get to use it that often so the car could be garaged for 6 months at a time, When I start and drive the brakes are nearly not there, push pedal to floor and not much happens, Do brakes on these cars go soft from lying up? also the car starts cold ok but when hot the car is very hard to start sometimes back fires, any ideas . Thanks Paul.

 

[219]

First it is a 300SL , and secondly this should NOT happen : you have a serious fault with your braking system which could be anything from a leak in your hydraulics , air or water in the system , a faulty master cylinder or servo .

This needs to be investigated and rectified before the car is used further .

Without knowing exactly what is wrong you may be risking complete brake failure .

The starting issue could also be any number of things from duff spark plugs , a fuelling issue with air locks appearing in the fuel line or loss of pressure due to a faulty fuel accumulator , a vacuum leak , or even moisture building up in the distributor cap ; all of these are known issues with the M103 ( or M104 if yours is the 24V version ) .

It is impossible to say more on either issue without seeing the car : it needs to be diagnosed by someone familiar with these vehicles .

 

[grober]

Sounds like you have a leakage in the inlet system which could lead to a weak mixture when the engine is hot and there is no longer mixture enrichment for cold starting. This could also lead to a lack of brake servo assistance leading to weak brakes. When was the brake fluid renewed last- it absorbs water which again leads to a soft pedal. As Derek recommends above it needs immediate attention before driving further. The R129 is a heavy car it needs the brakes to be in top condition!

 

[Paulmerc]

First it is a 300SL , and secondly this should NOT happen : you have a serious fault with your braking system which could be anything from a leak in your hydraulics , air or water in the system , a faulty master cylinder or servo .

This needs to be investigated and rectified before the car is used further .

Without knowing exactly what is wrong you may be risking complete brake failure .

The starting issue could also be any number of things from duff spark plugs , a fuelling issue with air locks appearing in the fuel line or loss of pressure due to a faulty fuel accumulator , a vacuum leak , or even moisture building up in the distributor cap ; all of these are known issues with the M103 ( or M104 if yours is the 24V version ) .

It is impossible to say more on either issue without seeing the car : it needs to be diagnosed by someone familiar with these vehicles .

Firstly how could I have made such a mistake, I must have been half asleep or drunk , of course you are correct its a 300sl , and thanks for confirming what I thought already, with regards to the brakes. Its always good getting a second opinion.

 

[Paulmerc]

Sounds like you have a leakage in the inlet system which could lead to a weak mixture when the engine is hot and there is no longer mixture enrichment for cold starting. This could also lead to a lack of brake servo assistance leading to weak brakes. When was the brake fluid renewed last- it absorbs water which again leads to a soft pedal. As Derek recommends above it needs immediate attention before driving further. The R129 is a heavy car it needs the brakes to be in top condition!

Hi Thanks for reply I will pass this info on to my mechanic and he can check and hopefully get the problem sorted. Paul. Dublin