Hard brake pedal

Post by **Louey** » 14 Apr 2008, 10:16

Occasionaly at the beginning of a journey the brake pedal is rock hard and takes a couple of minutes to become normal.

I'm guessing this has something to do with the vacum, but is it normal or is something on its way out - its been happening for about a year

Post by **tonytech** » 14 Apr 2008, 10:43

I seem to remember a post similar to this about 12 months ago.
It concerned a diesel engine that used a mecanical vacuum pump.

Have a search.

T

Post by **Louey** » 14 Apr 2008, 11:47

thanks Tony, did a search and it was Rob (lhd) who had a similar problem - I need to have a look at my vacuum pump first then move onto the servo end.

I will try the pedal test too.

Post by **Mocki** » 14 Apr 2008, 18:28

iirc its was crap oil that caused lhd's prob......

Post by **Louey** » 14 Apr 2008, 18:31

oil

now you've got me confused Steve. How does oil affect the vacuum???

Post by **dazzzer1** » 14 Apr 2008, 22:31

had a similar prob TWICE first time it was the non return valve on the vacuum hose which connects to the left hand manifold as you look at it, then the hose from this was collapsing. you can check the valve it should flow one way, just take it off and blow down it. jk do them and the are about £6 if i remember right

Post by **Laurie** » 15 Apr 2008, 11:44

The vacuum pump is affected by oil. What may be frightening is that the vac pump runs off the shaft that also drives the oil pump. That shaft is run off the back of the timing belt. If your oil is thick and cold, and the belt is a bit loose, the belt slips over the drive wheel and you don't get full oil pump drive or servo pump. You would be wise to run a semi synthetic or even a fully synthetic diesel oil and allow a minute or two to tickover on cold mornings.

Check your cam belt.
Watch your oil thickness.
Warm up a little before driving on cold mornings.

Post by **lhd** » 15 Apr 2008, 20:18

Hi louey,as previously mentioned check the non retun valve first.
easist way to check if thats ok is.
Leave parked up over night and before starting remove the vacuum pipe from the pump, if you hear a rush of air then you know its not a leak in the pipework or servo.
then start the van and put your finger over the pump opening.
If you have no vacuum for more than a few seconds then its either crap oil or a "feck" pump.....

I have one here if its the pump foc.

definitely do an oil change with a good oil first though.

All I did was an engine flush and filled it back up with the fusch oil from GSf.

I couldn't believe it would be the oil.

I changed the servo twice,and bought about four vacuum pumps,one brand new from vw @£140.00.

The oil pump didn't seem to be afected as I had no oil problems.

The problem with the vacuum pump is that it is lubricated through a small opening in the stem of the pump so when the oil is crap it takes longer to lubricate the inside of the pump.
The pump only produces a vacuum when the fins inside are lubricated.

I will never use tesco oil again...........

Post by **lhd** » 15 Apr 2008, 20:50

Louey pm me if you have any questions.

Rob.

Post by **Louey** » 15 Apr 2008, 21:15

I will do mate, thanks.

Hope I can get to look at the van after this weekend. Got my final assignment to be in for Monday so can't look at the weekend

Post by **lhd** » 15 Apr 2008, 23:30

Hope I can get to look at the van after this weekend. Got my final assignment to be in for Monday so can't look at the weekend

bloody students...............................................

Post by **Louey** » 16 Apr 2008, 22:17

Had a quick look in the engine bay tonight - bloomin thing is overheating and blowing cold air

my vacuum pump looks like

[img:493:373]http://www.bcn.net/~limbo/diesel2.jpg[/img]

no one way valve in sight