Brake pedal problems

[AlexD333]

So chaps, just a quick quiz, what controls the brake pedal "stiffness" after we had to stop due to heat I flicked off the ignition whilst rolling and pressed brake pedal, without the motor running it was very stiff. Now when I brake it works fine but if I release the pedal and back on again it goes really stiff and doesn't brake?? Haven't cleaned the drums yet but don't imagine it would do this? First brake is good, second consecutive brake is dreadful, 3rd is rock solid, seems to loosen off after 5/7 seconds again...?

A slight update too, seems another member had the exact symptoms I have since in the deep muck.

Now I want it to be crap in the brakes but the symptoms don't marry up? :nenau

First press is great, release and reapply it goes solid. So feel of binding.. :nenau

Rick suggested I look at vacuum pump and hoses. Near injector pump?

 

[Sweety]

The problem is you've got a girly right leg:lol it could be partly down to the amount of muck your truck is covered in don't forget the mud is drying & setting solid so i'd give it all a good wash down:thumbs I'm not sure if it was you or someone else on FB who mentioned their IC was covered in stones/gravel so I would check the hose coming off the brake servo as it could poss got nicked with a flying stone

 

[AlexD333]

The problem is you've got a girly right leg:lol it could be partly down to the amount of muck your truck is covered in don't forget the mud is drying & setting solid so i'd give it all a good wash down:thumbs I'm not sure if it was you or someone else on FB who mentioned their IC was covered in stones/gravel so I would check the hose coming off the brake servo as it could poss got nicked with a flying stone

Anyone got pics of this servo? Yes it was me :thumb2

 

[solarman216]

it is engine side of the brake pedal, with the brake master cyl on it, but it is not the servo you should be looking at, it is the small vac hoses on the turbo/alternator side, Rick

 

[elty001]

The engine has to be running for the servo to work as it is operated by vacuum. This will mean you have to press the pedal hard to get the brakes to work.

 

[terrano bob]

hi alex asked a marcanic at work tomorrow you do like to be the centre of attention yes its me im back :augie:lol:thumbs

 

[macabethiel]

The solid feel of the brakes with no engine running is perfectly normal for any car provided the engine vacuum has depleted. There may be some assisted braking for a few applications if there is any vacuum left in reservoir.

To eliminate it being anything to do with loss of vacuum try some serious cadence braking say at least half a dozen quick pumps of the pedal whilst moving at a few miles per hour. If you loose the power assistance effect or if the red brake warning light comes on you have loss of vacuum somewhere. (Assuming your particular model has a combined brake fluid and vacuum warning light fitted)

Otherwise sounds like it's mudded up.

 

[AlexD333]

Thanks Rick

And thanks all, but everyone has misread my symptom, I understand that the pedal will be stiff with the engine off :thumb2 however since doing so as I coasted over on the hard shoulder, now when I'm driving (with the engine on ) the pedal becomes stiff on second apply of pedal.

For example, you are approaching a roundabout, you slow with the pedal and also use the gears, you reach the desired speed so release the pedal, you then need to re apply the pedal a second time in a short space of time. ROCK... Pedal is solid :doh. After driving off again about 7 seconds later it is ok again..

There appears to be no signs of binding, I will take the wheels off and clean the brakes to check but suspect it's not mud in the brakes due to symptom above.

 

[Lazy-Ferret]

Still sounds like brake servo. Not sure what creates the vacuum on the later diesels, but I would start with the pipes.

IIRC you can do a basic test on the servo, I am sure Rick can fill this out, but it goes along the lines of...

With engine off, press brake pedal several times to remove all vacuum.

Then presd pedal down and start the engine.

If all is well, you should feel pedal sink a bit, then press back up.

 

[macabethiel]

Loss of vacuum

Thanks Rick

And thanks all, but everyone has misread my symptom, I understand that the pedal will be stiff with the engine off :thumb2 however since doing so as I coasted over on the hard shoulder, now when I'm driving (with the engine on ) the pedal becomes stiff on second apply of pedal.

For example, you are approaching a roundabout, you slow with the pedal and also use the gears, you reach the desired speed so release the pedal, you then need to re apply the pedal a second time in a short space of time. ROCK... Pedal is solid :doh. After driving off again about 7 seconds later it is ok again..

There appears to be no signs of binding, I will take the wheels off and clean the brakes to check but suspect it's not mud in the brakes due to symptom above.

My diagnosis still stands from what you describe you loose the vacuum power after the first application due either to poor vacuum production or loss of vacuum in the pipework. I used Silicon Vacuum hose and some copper pipework when I replaced mine all off e-bay for a fraction of the cost of Nissan Genuine Parts.

I had the problem you describe on my R3mr and it was a very small diameter perished hose that led to the low vacuum switch. Mine had about 8 various hoses between the servo and the vacuum pump. Some run very close to the exhaust front pipe. I changed all mine from pump to reservoir tank then those up the back of the bulkhead and all the small hoses from the T pieces to EGR valve and some other electrical stuff.

 

[Banshee]

I rest my case Alex :lol

Look at what all that lovely mud has done :doh

 

[AlexD333]

I'm gonna start with cleaning the shoes. Someone else from yesterday has exact symptoms, unlikely 2 of us with identical symptoms.

Lol don't blame the mud.. What are you fitting that Lokka for tescos carpark?

 

[Banshee]

I'm gonna start with cleaning the shoes. Someone else from yesterday has exact symptoms, unlikely 2 of us with identical symptoms.

Lol don't blame the mud.. What are you fitting that Lokka for tescos carpark?

Those trollies are a nightmare to get over!!!!!! :lol

Someone link him to the vid Steve took of me on Hollinsclough :augie

 

[Mobieus_uk]

i read someware that cars are designed to have 1 good press left in the brakes when the engine is off, this is so you can stop in the event of engine failure, after that it will be much harder

 

[AlexD333]

Those trollies are a nightmare to get over!!!!!! :lol

Someone link him to the vid Steve took of me on Hollinsclough :augie

I saw that video

I cleaned the rear drums to no avail today, however someone else who was at the pay and play had the same symptoms as me, he has since cleaned the slider pins in the front and it has returned to normal... Didn't think these symptoms would marry up but will try tomorrow... :nenau

 

[elty001]

Worth a try.if the mud has got in there then it will have dried once the brakes got hot.

 

[solarman216]

Alex FFS it is a lack if proper vacuum production that is your problem full stop mud in your drums wax in your ears are irelevant, Rick

 

[AlexD333]

Alex FFS it is a lack if proper vacuum production that is your problem full stop mud in your drums wax in your ears are irelevant, Rick

Yes knowing my luck it will be this, only reason I must try calipers is because someone else (with a Terrano) who also went though the same sandy mud also has the same symptoms as me, rock solid brake pedal. He rectified it yesterday by cleaning the front calipers

Although I don't doubt your expert knowledge I am preying it's just slider pins as much easier for me to remove wheels than search for phantom hoses

I'm a bit cackhanded don't you know :freak3:

 

[macabethiel]

Cleaning and greasing the calipers is always worthwhile but..

So if a brake caliper works on first application perfectly normally how can sand or mud stop it working a second time and then all fix itself a few moments later on?

Finding a perished hose is far easier than taking wheels off and stripping down calipers.

 

[Banshee]

So if a brake caliper works on first application perfectly normally how can sand or mud stop it working a second time and then all fix itself a few moments later on?

Finding a perished hose is far easier than taking wheels off and stripping down calipers.

Agreed :thumb2