Neptune1922

Neptune1922

Member
Returning cross country a 60 mile trip going through a built up area my brakes suddenly had an almost solid peddle and much diminished braking efficiency; not as effective as my old 109" drum braked vehicle! No warning lights and a quick check to the brake fluid levels indicated fluid in the master cylinder reservoir. I continued the remaining 40 miles, 30 on M ways, to home!
The Chassis was changed less than 500 miles ago! Does anybody out there have any ideas what has happened. (Raining where I'm so no look this morning)...
 
Simple question, are you sure it isn't just the ABS working? That can give a very hard pedal?.
But if it is constantly like that then I would suspect only half of the braking system is working and you'll need to look at the master cylinder seals, etc etc.
Easy enough to check once you can get it up on stands,
Bit surprised the red "brake warning light isn't on but thenI don't know what would put it on apart from low fluid.
Best of luck
 
Could be the ABS! However I would expect the SLABS ECU to light up a warning light or two. But thanks for opening that line of thinking.
When it first happened the pedal was soft, it was softer than usual after the new chassis, so I double pumped it and got a solid or almost solid pedal. (I haven't pressed that had since my 109" days). Some brakes but not really enough for safe driving. Fortunately I was on a v quiet 'A' road then a quiet 'M' way at about 20:30hr Sunday evening! Otherwise is would be a relay home and the last time I called on the RAC they took 17.5 hours to pick me up so I pushed on but a lot slower than I usually do that route...
 
Could well be. Leaking hose, hose come off, split diphragm......
But he implies that the brakes aren't doing their job despite him standing on them, which I don't think would be the case if he has lost servo, it'd just be a lot harder to make them work.
reminds me of when I lost half my brakes in a Cortina Mk3. Had to push like hell and even then they only just stopped the car even when driving slowly.
Could the vacuum pump be playing up?

Mate, how far down does the pedal go before you pump it, and do you get the vibration uinder your foot that you would get with ABS?
 
Stanleysteamer said:
Could well be. Leaking hose, hose come off, split diphragm......
But he implies that the brakes aren't doing their job despite him standing on them, which I don't think would be the case if he has lost servo, it'd just be a lot harder to make them work.
reminds me of when I lost half my brakes in a Cortina Mk3. Had to push like hell and even then they only just stopped the car even when driving slowly.
Could the vacuum pump be playing up?

Mate, how far down does the pedal go before you pump it, and do you get the vibration uinder your foot that you would get with ABS?
Click to expand...
If you've never driven a car without servo then you don't know how to stand on the brakes. More effort required than a car that doesn't have a servo
 
Check the vacuum hose to the servo to not be cracked or unplugged.... the ABS electronic system has nothing to do with that, it's a hydraulical or mechanical issue most likely something with the booster and related parts .... vacuum pump included
 
kermit_rr said:
If you've never driven a car without servo then you don't know how to stand on the brakes. More effort required than a car that doesn't have a servo
Click to expand...
My first car WITH a servo was probably a company car, and not even the first of the 4 I had.
I found the first cars with servos used to lock up too easily, until I learned how to pump the brakes. Of course they then had to go and overcompensate by fitting ABS. :rolleyes:
 
check the servo housing hasnt cracked.. had similar on mine and turned out to be a crack has formed between the mounting bolts . i stuck some superglue over the crack as a temp fix till i had it changed for a new servo
 
backinblack said:
I think the servo takes its vacuum from the alternator?
Click to expand...
Well, the vac pump is positioned between the belt pulley and the body of the alternator, but only if the engine is a diesel and not petrol.

I may be missing something, but the engine type hasn’t been mentioned by the OP… until then its a waste of time with suggestions as the vacuum system to the brake servo is different. 😊
 
All the above replies seem to relate to the air pump on the Alternator. The Alternator was replaced less than 200 miles ago! However with the engine running I pulled the servo pipe off the servo and held my finger over the disconnected pipe; the other end was still firmly attached to the air pump; no suction! Removed the Alternator and took it back to Craddock's. Arrived to find that, following the previous day's telephone conversation, there was a 'new' Alternator ready for me. Well done Craddock's!
Still got the problem of why the 'old' one failed and also trying to find a dry day, (Garage is full of my 88" undergoing a minor rebuild...).
Will update when it's dry...
 
Last edited:
I lost servo when my oil pump bolt let go even though the engine was still running so may be oil pressure related.
 
I changed the Alternator because its output was 14.63V and my battery that held a charge for over six weeks prior to the chassis change was now not holding a charge. The air pump / sucker(!) was not at issue indeed it was covered in oil, possibly affecting the alternator. Therefore I changed the Alternator on a one out one in basis. However I am not confident that there is sufficient oil flow as the new Alternator showed no sign of any oil. I am planning to check the oil flow by cranking the engine with the injectors disconnected; should only need a few revolutions; I hope.
In my situation I had no warning lights at all just an almost solid peddle and about 5 to 10% brakes. As a former Auto Electrician working in the Land Rover Service department I needed to change that Alternator or risk another 'cooked' battery. Why the air pump could not have its own position on the serpentine belt is a mystery to me but I suspect cost raised it's ugly head again on my TD5!
The old adage of, "if it ain't broke don't fix it" applied to the air pump but not the Alternator. Perhaps I should have not replaced the old, working, pump?
 
Yes! The system works well when the Alternator output is between 13.6V and 14.2V. Any higher and there is the probability of 'cooking' the battery i.e. boiling off the electrolyte and therefore reducing the batteries capacity to hold a charge. Also a battery voltage of 12.8V is considered normal and indeed all the electronics are designed to work between the above design parameters. Upon cranking if the battery volts is pulled down to 9V, by the starter motor running, then the electronics will not work to optimum eficency; and I was having starting troubles! High battery voltage may seem fine and useful and indeed all electronics are protected against the so called 'Lorry Start' when a 24V charger / starter is used to 'jump start' a 12V vehicle, but this protection is for extreme situations not everyday running. All filament bulbs and possibly some LED lights would suffer with high system voltage. Just try putting 15+volts across a standard filament bulb; it will shine bright, possibly very bright, but not for long! Some components can accept higher voltages like a starter motor for example and some cannot. A LED, for example likes 3V put 3.1V across it and no more LED. And indeed most Electronics work off a lower voltage than the battery and they are very expensive to replace!
 
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