brakes don't work properly on start up!

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KJT

New Member
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98
Location
Cardiff
I have a 4.6 1999 autobiography. When I start the car and make a u turn in my street, the brakes hardly work! But after about 30 seconds, they are ok. Is this normal? Myabs light comes on on start up and later goes our ok, so I don't think it's that. Can anyone shed some light on this please?​
 
What do you mean by hardly work? Do you mean for the same amount of travel when cold as when working properly you get litlle braking effect? Worth checking the servo and any vacuum pipes.
 
Its like the servo isnt working for that few seconds. Pedal travel may be a little longer at first start up too.The brakes are rubbish until then and its all perfect after that.
 
My 1996 4.6 is exactly the same if I move immediately post start up, but if I wait 10 seconds then it seems to be ok. I have no other braking issues.
 
mines the same as well. Just changed the fulid, no difference. Doesn't do it all the time, but i do have to wait about 10 secs
 
Mine USED to do the same .... it really used to **** me off ...so t'other week I sat down with Rave & had a reet good read .............

It didn't tell me owt I didn't already know so off I goes to my mate (Hes a Merc Mech) tells him the problem & he says .....

"Oh Aye, Mercs do the same especially the new E Class" It'll be air in the master Cylinder plus I bet no one has bled the Front & rear Nipples"

So, we sets to & gets our hands dirty ..... On the Master cylinder there are 3 nipples ( hard to locate as they're buried under tons of Foam insulation on the bulkhead)

See Section 70 Brakes / ABS page 817 on rave

Mine were tighter that a nuns chuff... never bin opened / bled since it left the factory...

NOTE*** You MUST proceed as per Rave or it won't work & there will be No Difference.

As I said did all nipples on mine .... COMPLETELY DIFFERENT CAR!!! Brakes work within 1/2 sec of firing her up & they stop you on a sixpence.. BRILLIANT...


NOTE TO "YOUNGER MEMBERS" .. Sixpence = about the same size as a 5p piece but worth half as much!!!
 
I have a 4.6 1999 autobiography. When I start the car and make a u turn in my street, the brakes hardly work! But after about 30 seconds, they are ok. Is this normal? Myabs light comes on on start up and later goes our ok, so I don't think it's that. Can anyone shed some light on this please?​
i belive this is quite normal , when you switch on your ign you can hear the brake pump working runs for about 30 sec or so ,when it stops the system is up to pressure the accumalator helps to maintain this pressure
when up to pressure you should be able to press the brake pedal 2-3 times before the pump kicks in to re pressurise the system
as goes for the abs light this will not go out untill all four wheels reach approx 5-7 mph:)
 
Ummm...... An interesting mix of ideas. I will have a listen to the 'pump' and see what I find. My gut feeling was that it was completely normal but not a good desidn idea at all (as when I do my 3 pointer in the mornings I nearly hit the curb and have to chuck the bx into reverse a bit lively!)
 
accumulator possibly.
Also does brake pedal feel clicky? if so there is known fault
 
Mine USED to do the same .... it really used to **** me off ...so t'other week I sat down with Rave & had a reet good read .............

It didn't tell me owt I didn't already know so off I goes to my mate (Hes a Merc Mech) tells him the problem & he says .....

"Oh Aye, Mercs do the same especially the new E Class" It'll be air in the master Cylinder plus I bet no one has bled the Front & rear Nipples"

So, we sets to & gets our hands dirty ..... On the Master cylinder there are 3 nipples ( hard to locate as they're buried under tons of Foam insulation on the bulkhead)

See Section 70 Brakes / ABS page 817 on rave

My front & rear nipples are starting to round with my efforts to move 'em. They are solid. Any advice on how to shift them ?

Mine were tighter that a nuns chuff... never bin opened / bled since it left the factory...

NOTE*** You MUST proceed as per Rave or it won't work & there will be No Difference.

As I said did all nipples on mine .... COMPLETELY DIFFERENT CAR!!! Brakes work within 1/2 sec of firing her up & they stop you on a sixpence.. BRILLIANT...


NOTE TO "YOUNGER MEMBERS" .. Sixpence = about the same size as a 5p piece but worth half as much!!!

My front & rear nipples are nearly rounded with my efforts to move them. They are sold. Any advice on shifting them >
 
use a single hex spanner, also a sensible tap square in end can release taper
 
If yerv finished lookin at GIANT rodents .. explain "Clicky" .. & What Known fault!?????
brake modulator shims break up, there is a repair kit from a bloke in either new zealand or oz (did mine)

during nomal use it will feel crunchy or as if it is rubbing, brake loss and hard pedal another symptom.
company is "range rover solutions"
 
Ummm...... An interesting mix of ideas. I will have a listen to the 'pump' and see what I find. My gut feeling was that it was completely normal but not a good desidn idea at all (as when I do my 3 pointer in the mornings I nearly hit the curb and have to chuck the bx into reverse a bit lively!)

Perhaps for 'Normal' you should read common. It's not right, but a lot of cars seem to suffer from it (mine included). They should be ok once the pump has generated enough pressure.

I might try The Hooded Claw's suggestion sometime. Wish I had a friendly mechanic like he has!
 
Ummm...... An interesting mix of ideas. I will have a listen to the 'pump' and see what I find. My gut feeling was that it was completely normal but not a good desidn idea at all (as when I do my 3 pointer in the mornings I nearly hit the curb and have to chuck the bx into reverse a bit lively!)

Nah, Claw's right. Bleed the system. And until you do that I'd imagine idling a few seconds when you start up and pumping the brakes a couple of times before setting off should spare the curb and your gearbox.

brake modulator shims break up, there is a repair kit from a bloke in either new zealand or oz (did mine)

Did ya? I'd be really interested to hear a bit about how complicated it was and what state you found the plastic shims in. Presumably yours is pre '99 and 2-wheel traction control? I'd started a discussion on the Oz solution here but you're the first I've come across who's actually done it.
 
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