brakes

[darryl]

hi all I need some help yesterday while popping up the shop my brake pedal suddenly went hard and I lost my brakes. if I push down really hard I can get a bit of breaking any ideas thanks

 

[Lazy-Ferret]

hi all I need some help yesterday while popping up the shop my brake pedal suddenly went hard and I lost my brakes. if I push down really hard I can get a bit of breaking any ideas thanks

First place to look is Vacuum leak to the brake servo.

Follow the pipe from the servo, as there are 2 places for the vacuum pump on the T2, one is down by the fuel pump, the other is a unit on the back of the alternator.

 

[jims-terrano]

Crickey scary stuff. Have you checked to male sure nothing is stopping pedal movement at all just to be sure.

Some kind of debris stuck in the front calipers perhaps?

 

[R1cho]

as clive says, vacuum pump and pipes, i'd go for the cheap option and check none of the pipes are blocked first, i know someone had the pump replaced and still didn't fix the problem turned out the pipe was blocked

 

[darryl]

First place to look is Vacuum leak to the brake servo.

Follow the pipe from the servo, as there are 2 places for the vacuum pump on the T2, one is down by the fuel pump, the other is a unit on the back of the alternator.

I will check that thanks

 

[Lazy-Ferret]

I will check that thanks

If yours is the one with the pump on the back of the alternator, might be worth checking your fan belts as well...

 

[macabethiel]

Heavy brake pedal - like pressing on concrete lol

Definitely sounds like no vacuum or loss of same to brake servo.

On my old r3mR Terrano it was the small diameter hose (screenwash size approx) between the servo feed and the brake vacuum warning lamp switch it was perished I replaced the lot with silicon tube. There was about 4 feet of the stuff from the vacuum reservoir tank to the servo. Some larger diameter obviously.

I don't think the standard Terrano has a warning light. My light had been flashing on sometimes over a few weeks but I thought it was a faulty handrake light switch as its a shared lamp on the dash.

It was a cheap fix thankfully.

Some of the pipework is quite close to the exhuast so it get some heat to help it perish

 

[rustic]

With reference to the vac pump, if faulty... I'm sure that one of the members, possibly Sparkie ? stripped down the vac pump on the back of the alternator, and I think refitted the rotor vanes the other way.

Another member lost vacuum too, and on investigation, it followed the fitting of a new front exhaust, and the fitter must have used a cutter, or welder during the operation, and damaged one of the vac pipes on the nearside inner wing.
On the front nearside inner wing, is a vacuum switch, and a fair few vac pipes, so it is important to check these out for damage leaks or poor connection.

Another Rustic Tip..
Moral of that particular story is... it is best to mention any recent work done to a vehicle prior to any new fault occurring. :thumb2
Rustic

 

[darryl]

hi I have checked pipes I cant see any problems with them what I did notice is there was oil in the pipe that runs to the servo and also the pipe under the pump the one that goes to the side of the engine. I done the brake pads about 6 months ago but have had no problems until now could it simply be that the brakes need bleeding? also are there any pipes I could remove with engine running to hear if pump is working? thanks

 

[macabethiel]

oil or brake fluid

hi I have checked pipes I cant see any problems with them what I did notice is there was oil in the pipe that runs to the servo and also the pipe under the pump the one that goes to the side of the engine. I done the brake pads about 6 months ago but have had no problems until now could it simply be that the brakes need bleeding? also are there any pipes I could remove with engine running to hear if pump is working? thanks

Are you sure its oil and not brake fluid ?
If it is brake fluid then the servo might be shot.
The brake fluid often looks black due to seal contamination.
Give it a taste if its bitter on your tongue its brake fluid.
Its a distinctive taste - do not worry it will not kill you to have a liitle taste!

You shold be able to check for vacuum function by removing the pipe at the servo end and sticking it on your hand with the engine running. There should be enough suction to pull on your skin and give you a little love bite! LOL

 

[jims-terrano]

Surely there shouldnt be brake fluid in the servo, should be in the master cylinder unless that has somehow leaked into the servo.

 

[darryl]

Are you sure its oil and not brake fluid ?
If it is brake fluid then the servo might be shot.
The brake fluid often looks black due to seal contamination.
Give it a taste if its bitter on your tongue its brake fluid.
Its a distinctive taste - do not worry it will not kill you to have a liitle taste!

You shold be able to check for vacuum function by removing the pipe at the servo end and sticking it on your hand with the engine running. There should be enough suction to pull on your skin and give you a little love bite! LOL

I tried this with the pipe off and there was nothing. There is a small diameter pipe that goes from the pump to a sensor this has pressure still when I disconnect the wires the brake warning light goes out

 

[macabethiel]

Vacuum track back

Surely there shouldnt be brake fluid in the servo, should be in the master cylinder unless that has somehow leaked into the servo.

Correct there should not be any brake fluid in the servo but the diaphragm has a pushrod that actuates the master cylinder. If the master cylinder develops a small leak it will be sucked into the servo and over time it can rot the diaphragm thus ending up in the vacuum system. This was common in the old days with poor seal materials but for the last 25 years or so seal design has improved hugely so its pretty rare.

I favour a lack of vacuum being the cause its just a matter of not jumping to conclusions that the vacuum pump has failed as its often a pipework issue as mentioned by others. If there is vacuum at the pump inteself I would then check the reservoir connections etc and work my way towards the servo. There is also the possibility that the pipes look okay but have collapsed internally.

 

[macabethiel]

pressure ??

I tried this with the pipe off and there was nothing. There is a small diameter pipe that goes from the pump to a sensor this has pressure still when I disconnect the wires the brake warning light goes out

Its vacuum not pressure that puts the light out so I am confused by your description. I would check for vacuum at the reservoir and the pump if no vacuum then the brakes loose all servo assiatance and you get a really solid heavy pedal. Its looking like the vacuum pump not sure if yours is on the alternator or seperate other members will know for sure.

 

[darryl]

Its vacuum not pressure that puts the light out so I am confused by your description. I would check for vacuum at the reservoir and the pump if no vacuum then the brakes loose all servo assiatance and you get a really solid heavy pedal. Its looking like the vacuum pump not sure if yours is on the alternator or seperate other members will know for sure.

The pump is on the alternator I have disconnected the pipe that runs from servo to pump that runs along the bulkhead and there is no vacuum at the pump so I think you are right :thumb2

 

[darryl]

Is the part I need actually called a vacuum pump when I order it thanks

 

[micktheshed]

Are you sure its oil and not brake fluid ?
If it is brake fluid then the servo might be shot.
The brake fluid often looks black due to seal contamination.
Give it a taste if its bitter on your tongue its brake fluid.
Its a distinctive taste - do not worry it will not kill you to have a liitle taste!

Or just try mixing it with water. Brake fluid will mix easily, engine oil will tend to globule.
Used to (‘70’s) use old brake fluid to lubricate the water pump seals by adding ½ pint to the coolant. Can’t remember why but it made the pumps last longer LOL. Don't reccommend it now as it's corrsive!