Vacuum pump

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Guest

Guest
I think my vacuum pump may be getting a bit tired, or alternatively I
may have a small leak in the vacuum tubing somewhere.

I was thinking that the brakes were maybe a little softer than I'd like,
so when the truck was serviced today I asked the mechanic to have a good
look. He bled the system, which has helped a bit, but also pointed out
repeated pumping of the brakes when at idle uses vacuum faster than the
pump provides it, causing the brake warning light to come on.

You have to pump repeatedly and fairly fast, but I'd be interested to
know how other people's brake systems perform in this respect to try to
get a feel as to whether I have a problem or not.

Any volunteers to go pedal-pumping at idle to let me know what happens?

And if I do have a problem does anyone have any experience of fixing the
pump? Or other things to look at, such as a leaky pipe? I know how to
use soapy mixture to look for air escaping, but are there any tricks for
finding holes in a vacuum hose?

Thanks

Christopher Bell
Devon, UK
1996 1HD-FT
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Hi Christopher
I Pedal pushed about 70 times at idle and all that happened was the pedal got harder and harder. I know from recent experience if the bleeding is shall we say not done enough your pedal will not be great.
I ended up bleeding mine twice after the Toy guy did it to get a hard pedal and still have not done the rear axel nipple yet. When i was bleeding and pumping hard the brake indicator light came on but that was when fluid was coming out of a nipple.
cheers
john 92HDJ 80 1HDT
 
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Christopher,
Before you start playing with the pump, take out and and thoroughly
clean the check valve in the vacuum reservoire (part No 44730-60050).
When it becomes leaky the symptoms will be as described.
--
Rgds,
Roman (London, UK)
'92 HDJ80
 
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John

Thanks, sounds like I may have a problem.

CB

Hi Christopher
I Pedal pushed about 70 times at idle and all that happened was
the pedal got harder and harder. I know from recent experience if the
bleeding is shall we say not done enough your pedal will not be great.
I ended up bleeding mine twice after the Toy guy did it to get a
hard pedal and still have not done the rear axel nipple yet. When i was
bleeding and pumping hard the brake indicator light came on but that was
when fluid was coming out of a nipple.
cheers
john 92HDJ 80 1HDT
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Roman
OK, I give in (because Mr Haynes doesn't mention it). I presume the
vacuum reservoir is part of the brake booster assembly, but where is the
check valve you mention? Any pictures / diagrams welcome!
CB
|
|Before you start playing with the pump, take out and and thoroughly
|clean the check valve in the vacuum reservoire (part No 44730-60050).
|When it becomes leaky the symptoms will be as described.
|
|--
|Rgds,
|Roman (London, UK)
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Chris.
The check valve stops vacuum returning to the pump when the pedal is
depressed. The reservoire is a round can in the engine bay on the
passenger side, tucked in the corner on the wheelarch. It sits in
between the pump and brake booster. It has two connections - one is
the vacuum rubber hose, the other one is electrical for the pressure
switch (if you disconnect the switch altogether the light on the
dashboard will go off).
The valve can be undone in situ. Take it off and clean it as best as
you can. If it is corroded insaide, a new one from AAI will cost you
ca 27 euro + tax.
Hope it helps.
--
Rgds,
Roman (London, UK)
'92 HDJ80
 
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Roman
Thanks.
I'll have a go "later".
CB
|
|The check valve stops vacuum returning to the pump when the pedal is
|depressed. The reservoire is a round can in the engine bay on the
|passenger side, tucked in the corner on the wheelarch. It sits in
|between the pump and brake booster. It has two connections - one is
|the vacuum rubber hose, the other one is electrical for the pressure
|switch (if you disconnect the switch altogether the light on the
|dashboard will go off).
|
|The valve can be undone in situ. Take it off and clean it as best as
|you can. If it is corroded insaide, a new one from AAI will cost you
|ca 27 euro + tax.
|
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G

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Well my HJ60 will use up the vacuum and bring the warning light on when on
idle after about 5-6 pumps. It is a 1982, with 210,000 miles, and the pipes
or pump have never been serviced or replaced. I bought it off the first
owner when it was 8 years old, and it has never given any problems.maybe
this is tempting fate even mentioning the fact...If it packs up tomorrow,
can you send me your address, so I know where to send the bill :)

Neil
 
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Rui
Thanks for that. I reckon my build date was 1996 and I've just checked
the VIN and it is outside that range, so I can't get it fixed free :-{
When it stops raining I'll get the spanner in there and see if I can get
that non-return valve out. At the moment, just by looking, it's not
obvious. Is it on the end of the rubber tube from the brake booster? Or
is it part of the (rigid) tube connection to the vacuum pump? (Questions
for Roman I think).
Christopher Bell
|Hi guys,
|
|Don't know if you're aware of this recall. Don't know
|either it it's the same problem but it might help.
|
|http://www.vosa.gov.uk/vosa/apps/recalls/searches/expand.asp?un
|iqueID=3DEE4BDAE21E7D013B80256BB90026926E
|
|For all other vehicles:
|
|http://www.vosa.gov.uk/vosa/apps/recalls/default.asp
|
|Here in Portugal some KZJ90 were recalled last month
|for some defective halfshafts - about 10 years later
|they were on sale!
|
|Fortunately, for this reason and others, we can't
|really complain about Toyota dealers. ;-)
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Roman
Thanks, that's what I rather thought - but the diagram makes it a lot
clearer.
CB
|
|Chris,
|
|Look here: http://tinyurl.com/ymm7rh
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Hi Rui
How do you know where to look for the recalls for the Toyotas.
cheers
john 92HDJ 80 1HDT
 
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