No brakes?! Arrgh!

[pete_s60]

Over the past few days in my partners V40 (2000) the first journey of the day, the first time you brake... nothing! Its really worrying.

After the first panic, the rest of the journey is fine!

The disks and pads are all fine, the fluid is fine, normal colour - plenty of it.

Its odd that its only the first time you go to use the brakes each day and from then on its fine...

Any ideas anyone?

[phil_woods]

Over the past few days in my partners V40 (2000) the first journey of the day, the first time you brake... nothing! Its really worrying.

After the first panic, the rest of the journey is fine!

The disks and pads are all fine, the fluid is fine, normal colour - plenty of it.

Its odd that its only the first time you go to use the brakes each day and from then on its fine...

Any ideas anyone?

could it be the servo?

My astra used to do it every once in a while all of a sudden there would be nothing in the pedal, replaced the servo and bob was my uncle!

[kevin4878]

scary thought that, not a good position to be in

[pete_s60]

We tested the servo by putting a small amount of pressure on the pedal, then turning the engine on.... the pedal should at that point depress about half an inch again.

I spose it could be a an intermittent fault with it?

By driving along, then turning the engine off completely... that would give the same sensation in theory then? As in.. no power assistance? Just wondering if thats worth doing and seeing if it feels the same as when they just go.

[phil_woods]

it happened to me once when I was in the fast lane on the motorway, traffic started slowing down and my brakes weren't there!
No exageration a little bit of poo came out and I had to slow down with the handbrake, luckily it was all ok and I managed to pull onto the hard shoulder!

[pete_s60]

Its is a heart stopping moment!!

[jay30h]

If its a GDI engine the servo vacuum hose from the inlet manifold may need cleaning its a routine service item and oftern overlooked

[pete_s60]

It may seem like a silly question.... but new to the whole Volvo thing. Whats a GDI engine? :s

[jay30h]

It may seem like a silly question.... but new to the whole Volvo thing. Whats a GDI engine? :s

Its the mitsubishi engine, direct injection petrol ,they get a lot of bad press and from my experience its undeserved, the one we own has been superb. if its the gdi model you have it will look like this

[pete_s60]

Cheers dude.

Dont think its a GDI from looking at it. Its sounds very much like it could be the servo at fault tho, before replacing anything however, a change of fluid and a good thorough bleeding is called for I think. Although the fluid looks good I have no idea when / if it was last changed.

[jimka]

this can be the electronic brake distrubtion kicking in too early and causes the peddle to feel really light and feel as if its not working! my MY2003 volvo s40 diesel use to do it

[pete_s60]

The electronic brake distribution, when that cuts in does it feel or sound at all like ABS?

It feels very smooth and there is no ABS type noise, they just don't work randomly!

[jimka]

nope, didnt make a noise on my car...


not ruling things out, you might have a leak somewhere, a split hose or an intermittent brake booster caused by a leak or stuck return value, take your car to a garage and get them to look at it asap... no brakes are quite scary!

[nobananas]

I'm assuming this vehicle is petrol ?

[thebadger]

Did the pedal go "light" or was it "solid"?

I had the main servo vac hose "pop" off it's main post on the manifold once.

Stopping a heavy V70 T5 from 40mph on a dual carrige way just after the turbo has kicked in is quite possibly the single most scary thing I have ever had happen to me.

I now chase spiders!

If it went "solid" then the vac line (or the plastic "tree" it hooks into) will be at fault.

I think I spent £17 for a new part off Volvo. I drive happier with that £17 spent!

[thebadger]

Also if there is a major vac leak, that will also mess the vac on the servo & cause light or powerless barkes...

Check all the hoses & their connections.

[pete_s60]

Sorry for the delay in posting back! - Been working lots :-(


nope, didnt make a noise on my car...


not ruling things out, you might have a leak somewhere, a split hose or an intermittent brake booster caused by a leak or stuck return value, take your car to a garage and get them to look at it asap... no brakes are quite scary!

I shall check all the pipes over the car at the weekend... Theres nothing leeking within the engine bay, but not had a chance to look elsewhere yet.




I'm assuming this vehicle is petrol ?
Its a petrol - Its a 1.8 (Not a GDI engine) Are brakes on diesels different? :-s




Also if there is a major vac leak, that will also mess the vac on the servo & cause light or powerless barkes...

Check all the hoses & their connections.
We checked the vac hoses and the one way valve where it plugs in... nothing major untowards there - Stopping a V40 at that speed was scary! I would imagine on a duel carriageway in a V70 was a bit of a brown trouser moment!



Cheers for all your help guys! - Its really appreciated!

I dont like letting garages do the work unless totally unavoidable, more out of principal then anything else...

That said my S60 is in as I type to have the inlet Venturi valve cleaned... apparently that will stop it stalling? :-s Fingers crossed!!

[nobananas]

The servo on diesels gets it's vacuum from a mechanical pump rather than from engine vacuum from the inlet manifold, no throttle butterfly to 'suck' against in a diesel you see (well at least on older diesels). After you have turned off the vehicle can you pull the servo pipe from the servo, it should still have vacuum and hiss audibly as you try to remove it.

[thebadger]

When my car had the issue (the hose had "popped" off for my dual carrigeway moment) the attatching point (plastic pipe the size of your thumb) had a hair line crack (I missed this), which later caused a massive amounts of misfiring & occasionally just after lift off, the brakes would go very light.

This is basically an imbalance in the available suction for dealing with the systems that use them.

Sudden lift off reduces the available suction for just a moment, but if there's a hole in the system, this will drain the immediate available suck until the draw available is greater than the loss generated by the gap. (like putting on a sprinkler with a hole in the hose, until the pressure gets high enough the water will just trickle out the hole)

The gap may not be obvious, like I say my leak was in plastic pipework hidden by a joint in the pipe.

HTH

[nobananas]

The brake master cylinder also has a seal where it joins the servo, if this is leaking you will also loose servo vacuum.

[pete_s60]

Ill check for hairline cracks and where it all joins the master cylinder this afternoon... I hope I find it!! - Its booked in with Volvo tomorrow :-S

[pete_s60]

I think its time to take it up to the cambridge garage?!... We've looked at everything suggested here, checked from hairline cracks as best we can but cant see anything that could cause lack of brakes.

Annoyingly the problem seems to have gone away! - I dunno whether its just because we've taken a few bits apart or what... We didnt find anything wrong tho :-s

Not sure whether to be happy it seems fixed, or take to the Garage anyway, as its the brakes Im not sure i wanna find out its in fact not fixed when Im on the motorway.

[thebadger]

May have been a loose hose connection, but you've tweaked it & now it's fine.

Best advice is some new hose clamps, might give you some more confidence.