Just about took out driveway gates this morning when brake pedal went to the floor - whipped handbrake on.
Had a master cylinder replaced 18 months ago and about 10 months later brake hose cracked - replaced brake hose and few months after that the master cylinder went due to a seal being torn when brake hose went.
The brake company that supplied the master cylinder diagnosed and repaired the seal problem about 8 months ago (master cylinder kit).
The brake pedal feel seems different this time - it still half pie pumps up but feels like their a 4 to 5 inch steel pole between the brake pedal and floor at end of brake pedal travel. (no spring whatsoever)
Can drive the vehicle through the brakes when pedal fully depressed. Was coming to a complete stop eventually last time - truck nose was diving down - this time slows vehicle down but slowly runs on when pedal fully depressed.
Finally when start truck up and pump the brake pedal - a hissing of air or the pumping of fluid can be heard. (Not sure if booster working and just hearing new things cause listening for it ?)
Any ideas what problem could be ?
Cheers
intrade,
Dec 16, 1:40am
whats the fluid level of the brake bowl make sure you check whole it should have 2 chambers if one is empty the other might read full.
mals69,
Dec 16, 1:43am
Brake fluid looks not to have dropped
mals69,
Dec 16, 2:00am
Pretty sure it just the one big reservoir on this model with front and rear brakelines leading off - will check though when can .
Cheers
therafter1,
Dec 16, 2:06am
Check back of alternator to see if it is one of the models with the vacuum pump built into the back of it.
ema1,
Dec 16, 2:10am
If you are having varied brake problems from different sections of your brake system, I would recommend overhauling the complete system not just parts of it. After all the whole system has had the same duration of use over time . right? Brakes are things not to be messed with, overhaul ALL of the system if you are having issues like you're experiencing. Brake specialist company would be a wise move to sort it out PROPERLY. Just think . a Nissan Terrano being a heavyish vehicle is quite a lump of a thing to have a collision with if it has no braking capacity at any time. I would say going by your brake system problem description that the booster diaphragm or other booster components have gone "belly up" and the master cylinder is failing again and it's my bet that brake fluid is also leaking fluid into the booster body.
therafter1,
Dec 16, 2:23am
If its an import Terrano that has been to the moon and back two or three times and had the odo flicked for good measure then all of the above is more than probable lol
ema1,
Dec 16, 2:28am
If as you say you had to replace a burst hose at one stage then it's also a fair bet that all the other hoses in the system won't be far from failing as well given their age? I am a believer in replacing ALL hoses if you have a failure in one as the others will no doubt be suspect too? Who's to know if other hoses are in a similar condition to the one that did burst. again I say brakes are things not to be trifled with, overhaul the whole system not just part of it . period. Vacuum pump and vac hose to booster needs to be checked as part of a brake system overhaul along with pedal and pivots for possible wear/cracking etc, it's not unknown. so be wise do a complete overhaul, that way you will know what you have got! Aircraft don't have half arsed jobs done on them, their systems are all serviced at strict time constraints for good reason! Apply that to ground vehicles and failures will bound to be a lot less frequent or indeed serious or similar maybe fatal!
intrade,
Dec 16, 2:28am
next thing hissing is the vaccume system has one or more leakages . Now there is something one should learn as it is important in loads of ways. There is no such thing as a vaccume. what it is is a difference in pressure, meaning its less pressure what we call a vaccume , true vacume is only out in space . Now i dont know if you know this but this is often important to know the true fact. We live in about 1 bar atmosphereic pressure.
So air is leaking in to your vaccume system if you hear a hiss. that is what is happening and not the vaccume escaping lol. might be funny to read but its a important fact. volumetric efficiency of engines all-sorts is affected by this stuff also.
ema1,
Dec 16, 2:42am
Exactly the reason is a vacuum ( or depressed air if you like) is not being maintained due to a leak allowing outside atmospheric air to enter the "vacuum?" system. In doing so what is eventually happening is the air inside the system is going to balance the atmosphere outside rendering it non functional. A leak is a leak no matter what direction it goes intrade, in this case it is outside air leaking inwards as you say, basically trying to balance the internal and external air pressures. simple as that. Plus the "vacuum" being formed in the booster body also acts on the rear seals of the master cylinder and if these are in anyway defective they will leak brake fluid into the booster body. and if excessive the "vacuum " provided by the engine if petrol type will suck brake fluid into the combustion chambers thus emitting clouds of white smoky steam/smoke like crap out the exhaust. In a diesel the vacuum pump will eventually suck brake fluid as well and expel it through a vent in pump somewhere?
mals69,
Dec 16, 2:49am
Good point - yes it is that model
mals69,
Dec 16, 2:58am
I hear you loud and clear about brake importance - good valid points, appreciated them. Said to a mate this morning probably booster but he said would not be the case as you still got brakes, should of said to him not called a booster for nothing lol. Thanks along with intrade for saying most probably booster
Might be time to pass my much loved truck to mrs who can do a brake overhaul when her emurade shits itself, and I'll trade up to a D40
mals69,
Dec 16, 3:03am
Interesting info intrade cheers
Could it also be the vaccume pump therafter speaks of - is it meant to be sucking like a good girl if pull the hose off the booster with motor running ?
ema1,
Dec 16, 3:09am
Somewhere down below the fluid level there will be a division partition in the reservoir to maintain one or other section of the split brake system functional if either half fails so you have some form of braking until remedied properly. Foot going to the floor would suggest failure in the hydraulic system and if fluid level remaining the same I would suggest another master cylinder failure ( possibly bypassing in the cylinder itself). Check at all wheels for possible fluid leaks ( wheel cylinder and or caliper failure) as well as other likely fluid leak places in the WHOLE system. Be prudent overhaul THE WHOLE SYSTEM ! Suggestion to disconnect vac hose to booster and run engine to see if vac pump is functioning the way it should is a good one, they do tend to wear as well and the alternator mounted pumps function a very high RPM (alternator speed?) The vac pump also comes under the "WHOLE SYSTEM "overhaul that I'm talking about.
mals69,
Dec 16, 3:46am
Cheers yeah did routine checks this morning for leaks on all for corners, under bonnet. Take it meant to suck the vaccume pump ? - if disconnect hose at booster how much suction should be there i.e enough to suck onto my neck and give myself a hickie ?
mals69,
Dec 16, 3:48am
Oh yeah has the partitions all covered with fluid. Had a thought might be able to import whole new brake system off ebay etc
ema1,
Dec 16, 5:44am
Yep if it does "suck" strongly then that narrows the problem search down to a combination of booster and master cylinder malfunction or even a leaking vac hose between pump and booster but with pedal going full down and no braking resulting it's my bet the booster & M/cyl is where your problem lies. Replace them and all hoses and service the rear wheel cylinders and front brake calipers or wheel cylinders (depending whether it's all drum brakes or disc front drum rear system.) Good idea to replace both booster and M/cyl with NEW items as a pair at the very least, as quite likely your existing system has past it's use by date! As a matter of course check the push rod from pedal and pedal pivot for wear enough to make pedal ineffective but that's not all that likely but important to check pedal system for wear non the less, and check pedal box frame for cracks too is a wise move? Is there any adjustment system between brake pedal to master cylinder gear as some makes do have , if so is the system adjusted correctly or is the set up between pedal and M/cyl a preset non adjustable type? Also how recently has the brake fluid been replaced, prior to the earlier brake problems I'd hazard a guess probably was long over due, due to being an import I'd say highly likely actually.
ema1,
Dec 16, 5:59am
Probably cost effective too, best solution ultimately I think, Nissan OEM genuine is best for items designed for the vehicle. Vehicle numbers /years/models . would be critical when ordering parts as no doubt there would be various subtle differences between models/years versions etc, etc
mals69,
Dec 16, 6:04am
Cheers ema for all the info
The brake fluid been replaced few times. Not sure if adjustable between brake pedal and master cylinder but will have a look.
Good idea about pedals etc for cracks.
It has not visited the moon yet - only 175000km, guess with being 24 years old now things perish. Lot of years of brake fluid residing.
sr2,
Dec 16, 6:57am
Wow, there??
mals69,
Dec 16, 7:24am
Crikey you trying to turn me into a hairdresser with no taste ?
mals69,
Dec 16, 7:31am
Think he just getting at checking over system and doing preventative maintenance.
Will do the suggestions and see if can narrow it down, would have to be mobile mechanic with it being to dangerous to drive.
Cheers
sr2,
Dec 16, 7:47am
Full marks for being charitable my good man!
poppy62,
Dec 16, 7:59am
Nothing wrong with a good barber who owns quality Euro.
mals69,
Dec 16, 8:15am
They both got something in common - old fashion.
Snip goes the shears - flattened merc goes the steam roller
God that thing ugly - you having a laugh eh surely not serious ?
How many times did it get beat with the ugly stick or did they lose count ?
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