No brakes if you press em twice.

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
landowner

landowner

Pensioner Pete
Full Member
Posts
13,222
Location
WA2
Well no servo assistance if you press them three times in qick succession actally.
Dunt take long for my new purchaces to go wobbly, the servo hisses when you press the brakes, even hisses if I press the brakes :D

Never did it when I bought it but hey, can fix it, give me summat to do on these long freezin winter flippin evenins eh:(

Now then, would it be the servo or the pump or both dya think??
 
It is almost unheard of for a servo to fail.

They always HISS when you (or I) press the pedal. The servo works by letting air IN when you shove the pedal. This air goes in around the pushrod the brake pedal lever shoves into the servo.

Sounds to me as if the vacuum pump isn't sucking as it should.

CharlesY
 
nicedayforit said:
Two things,
The non-return valve on the connection to the servo is faulty.
The vacuum pipe connection to the vacuum pump has split.
The hiss when you press the pedal is normal.
Click to expand...


I don't want to appear picky ... but ... is that not THREE things?

What if the vacuum pump is buggered?

CharlesY
 
CharlesY said:
I don't want to appear picky ... but ... is that not THREE things?

What if the vacuum pump is buggered?

CharlesY
Click to expand...
Not had time to check it today but are the vac pumps prone to failure? having said that I am on 135ish thousand miles so timing belt due and it could do with a good service.
 
landowner said:
Not had time to check it today but are the vac pumps prone to failure? having said that I am on 135ish thousand miles so timing belt due and it could do with a good service.
Click to expand...


Yes, they do fail, and the hose to the servo is also prone to splitting and leaking INWARDS.

People here would suggest you check those items first.

Take the vacuum pipe off the servo, and with the engine running put a finger over the open end of the pipe. There should be a good suck.

CharlesY
 
Right.
Brakes went to the floor today as if there was a massive fluid leak. Tried them again and still sinking to the floor so I drove home without using the brakes and took a quick look.
No fluid loss so not a pipe or owt so it must be the servo, brakes working ok but pedal sinks if I use prolonged pressure on pedal.

Am I right then ?? is it the servo ?? I cant see any fluid loss and the resevoir is still on the mark, there is a definate chuff of air as the pedal is applied and I dont think that is normal, maybe a little hiss but not a chuff if you know what I mean.
Pedal actually went to the carpet during a hard braking sesion to induce a broadside skid on the ice,,,worked an all:D
 
More than likely he SERVO has NOTHING to do with the pedal going to the floor, which is almost certainly being caused by a fault in the hydraulics, probably in the master cylinder.

No part of the servo is involved with the hydraulics. The ONLY ways the pedal can sink are (1) there is a leak of fluid (you think not), (2) there is a caliper with one or more stuck piston(s) that are springing so far they let the pedal hit the floor (you should see a rusty disk in this case possibly only on one side of a disk (3) one of the main pressure seals in the master cylinder is letting fluid pass back, which will let the pedal go down but there will NOT be a leak to the outside.

You need to get this sorted smartish I reckon.

Let us know what it turns out to be.

CharlesY
 
CharlesY said:
More than likely he SERVO has NOTHING to do with the pedal going to the floor, which is almost certainly being caused by a fault in the hydraulics, probably in the master cylinder.

No part of the servo is involved with the hydraulics. The ONLY ways the pedal can sink are (1) there is a leak of fluid (you think not), (2) there is a caliper with one or more stuck piston(s) that are springing so far they let the pedal hit the floor (you should see a rusty disk in this case possibly only on one side of a disk (3) one of the main pressure seals in the master cylinder is letting fluid pass back, which will let the pedal go down but there will NOT be a leak to the outside.

You need to get this sorted smartish I reckon.

Let us know what it turns out to be.

CharlesY
Click to expand...

I hear you and it's looking like the master cylinder.

I have a spare so will swap it after xmas and see what transpires.
Not had a problem tonight, brakes back to normal so could well be a seal problem when under high pressure. Strange one this and me not being used to servo problems dont help.:rolleyes:

Should have said cars with servos and brake problems, take the servo off and I'm a wizz with brakes me..
 
landowner said:
I hear you and it's looking like the master cylinder.

I have a spare so will swap it after xmas and see what transpires.
Not had a problem tonight, brakes back to normal so could well be a seal problem when under high pressure. Strange one this and me not being used to servo problems dont help.:rolleyes:

Should have said cars with servos and brake problems, take the servo off and I'm a wizz with brakes me..
Click to expand...

Good Lad!

The servo is a purely MECHANICAL device.
The only way the pedal can go down is if hydraulic fluid gives way AFTER the servo.

Your mission (if you care to accept it) is to find out why the hydraulics are giving way.

Then you can come up here and fit new brake pipes to my Disco TD5.

CharlesY
 
CharlesY said:
Good Lad!

The servo is a purely MECHANICAL device.
The only way the pedal can go down is if hydraulic fluid gives way AFTER the servo.

Your mission (if you care to accept it) is to find out why the hydraulics are giving way.

Then you can come up here and fit new brake pipes to my Disco TD5.

CharlesY
Click to expand...
Make me own brake pipes, used to fettle track car brakes, no servo's on Caterhams and Elises, better without them on a light car. Peoples just drive em these days and dont change fluid or maintain brakes then they wonder why the pedal goes to the floor after two laps.:rolleyes:

Any way Merry Christmas to yer, I'm off to help santa with the presents and the sherry.:D
 
Default Re: No brakes if you press em twice.
Quote:
Originally Posted by CharlesY View Post
What if the vacuum pump is buggered?
CharlesY
Er, I don't think we should go there...

Hmmm..... is there something you don't want to tell us that we would want to know?

CharlesY
 
Hmmm..... is there something you don't want to tell us that we would want to know?

CharlesY[/quote]


I don't think the vac pump is buggered. But it might be. There again it could be the servo. Or it could be the master cylinder.
Not checked anything properly as it's fffflippin cold an it's christmas.
Done some armchair theorising and some tests from the drivers seat and checked the fluid level and checked no fluid dripping anywhere when stood.
Hit the pedal acouple or three times with engine off and pedal goes solid as it should and dosn't sink. Phew..
Start engine and let it build vac up then press the pedal very hard and it sinks down to the solid bit.
Can't remember the test that one does from the drivers seat to check the servo but brakes have been ok under normal use so will have a look next week.
Thanks for input :)
 
You must log in or register to reply here.

Similar threads

R
Brake peddle is soft - no brakes
Replies
13
Views
1K
nobber
nobber
M
Range Classic 1990 V8 Brake Light On
2
Replies
20
Views
2K
Madcal
M
jointlywise1
Freelander 1 Brakes 2003 td4
Replies
9
Views
1K
andyfreelandy
andyfreelandy
H
Brake servo confusion!
Replies
12
Views
2K
Bobsticle
Bobsticle
CohPC
4 months of owning 1974 series 3
Replies
4
Views
1K
CohPC
CohPC
Back
Top