brakes need lots of pressure and engine running a bit rough.

#1
Hi there,
I have been using the car fairly frequently and today on my return trip from town , I noticed that I had to use a lot of pressure to stop the car when braking. The brakes were working fine up until then. When stopped it was running a bit rough and not its usual smooth self.
I opened the bonnet the only change that I could detect was that there was oil traces around the D/S rocker cover from the vent with the flame trap in the line.
The pipes were all connected to the brake servo unit and in good condition.
Peter
 
#4
today checked the pipes and did the test recommended by disconnecting the hose, result the engine ran smoother.
reconnected the hose, put a new small short hose on vacuum unit itself and secured with hose clips, no change, no brake force etc.
Noticed that if I apply the brake with the engine on tick over, the engine shakes, remove foot from brake and smooth again.
so it definitely points to a faulty booster unit. It will cost $650 to have it rebuilt and 3 weeks off the road.
It is going to be a trial, as this in my every day car at the moment and I live out in the country....no bus either :(
Peter
 
#5
Hi peter,
I think i still have a spare unit and some kits here. I've just bought a place up at Bulahdelah and should get up there this coming weekend. I'm crook at the moment. I could come by and have alook at it as there are a few cheaper fixes than a complete rebuild. I'll see what i have as i could post one up and you could just do a change over while yours is repaired.
Michael
 
#6
Hi peter,
I think i still have a spare unit and some kits here. I've just bought a place up at Bulahdelah and should get up there this coming weekend. I'm crook at the moment. I could come by and have alook at it as there are a few cheaper fixes than a complete rebuild. I'll see what i have as i could post one up and you could just do a change over while yours is repaired.
Michael
Hi Mike,
Thank you for the kind offer, that would be great.
Peter
 
#7
Yesterday I stripped a spare servo unit that I had. It did not take very long.
There is virtually nothing inside , just the large rubber diaphragm and an enormous spring.
All the rubber parts were in good condition too.
There was a lot of hydraulic oil in the container , so the seals on the plunger must have been leaking.
I was amazed at what a simple construction it is.
I too then puzzled at how air could leak in or out and found nothing to blame?
Having checked my faulty booster, I am at a loss as to where the air leak is?
Peter
 

roverp480

Active Member
#10
Yes. Just to add a little extra. with brakes off and engine running there is a vacuum on both sides of the diaphragm, the spring pushing it to one end. Then braking, the air valve is opened allowing air into one side which pushes it with the hydraulic cylinder, adding to the braking effort. If the valve isn't sealing, air is entering all the time and thus no vacuum.
 
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#11
that is the main cheaper fix I was thinking of. I'm afraid i'm still not well enough to travel but I will get into the storage and see what i can post up.
there are two valves on the same shaft one either side of the white plastic disc, passing through the middle of it. Normally it is the lower one(s) that go. Do you have the manual? It is explained in 70.50.01, You can do it in the car, just beware of the springs when dissassembling. You probably won't need to remove more than the plastic bits but I have all the gaskets (and the seals) if you do.
 
#12
that is the main cheaper fix I was thinking of. I'm afraid I'm still not well enough to travel but I will get into the storage and see what i can post up.
there are two valves on the same shaft one either side of the white plastic disc, passing through the middle of it. Normally it is the lower one(s) that go. Do you have the manual? It is explained in 70.50.01, You can do it in the car, just beware of the springs when disassembling. You probably won't need to remove more than the plastic bits but I have all the gaskets (and the seals) if you do.
hi Mike,
get well soon...
I have a reconditioned servo in the post from Winns. They sell kits of all the parts needed to recondition a servo, and I almost bought the kit, but Geoff, the owner of Winns, advised me that the kits have a reputation for not working and that the only way to be sure was to buy the complete refurbished servo that he sells, that has been sleeved in S/S .
So that is the option that I have gone for.
I completely striped a spare servo unit that I had, to see how it all worked and went together.
The most difficult part to remove was the metal air valve directly beneath the white plastic upper air valve.
I eventually got it out by using CRC rust remover and air and tapping upside down on the bench, (every force has and equal and opposite force theory) o_O
It was just very stiff inside the bore, the rubber seal holding it in very well.
To do that job without removing the complete unit would be almost impossible.
Peter
 
#13
update:
today I removed the offending unit and stripped it down to its bare bones and guess what I found?
oil in and behind the large rubber membrane, so the oil must have come from the shaft that moves when the brake peddle is pressed?
after removing the rod with the seals on it, I inspected the bore of the front part and it appears that the small air valve bore has been re-sleeved in brass and the main bore , I'm not sure, but looks like it may also have been re sleeved.
I will take it into a local machine shop that I frequently use and ask there opinion.
Then make a decision as to sleeve or not to sleeve, that is the question, to suffer the slings and arrows of misfortune , or get a re-sleeve.
Wins sell a very expensive kit (over $200 AU ) with lots of parts that are not needed if the original parts are serviceable, so where do I just buy the seals for the rod, only 2 of them !
Peter
 
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#14
Peter,
I recently overhauled my servo ( around 2 years ago) and after that I noticed that I was loosing brake fluid from the level in the reservoir. This was a very small leak that I couldn't find and removed the servo twice since I was blaming the seals in the servo but did not find any oil. Lately the leak increased and I found that the master cylinder was leaking and the oil was dribbling down in front of the firewall onto the suspension. I replaced the seals of the master cylinder and the leak stopped.
What probably happened was that when I bled the brakes by pimpingumping the master cylinder, the seals were damaged. So in my opinion , while you're at it replace/recondition the master cylinder. Some will now come back saying I should have used an eazi bleed system or something similar - unfortunately I don't have one so I resorted to what the manual says.

Regards
Richard
 
#17
Peter,
I recently overhauled my servo ( around 2 years ago) and after that I noticed that I was loosing brake fluid from the level in the reservoir. This was a very small leak that I couldn't find and removed the servo twice since I was blaming the seals in the servo but did not find any oil. Lately the leak increased and I found that the master cylinder was leaking and the oil was dribbling down in front of the firewall onto the suspension. I replaced the seals of the master cylinder and the leak stopped.
What probably happened was that when I bled the brakes by pimpingumping the master cylinder, the seals were damaged. So in my opinion , while you're at it replace/recondition the master cylinder. Some will now come back saying I should have used an eazi bleed system or something similar - unfortunately I don't have one so I resorted to what the manual says.

Regards
Richard
hi there Richard,
Thank you for your reply.
I will now check out the master cylinder for defects and advise what I find.
Peter
btw its a very difficult place to access, so I will have to exercise the utmost patience and place my swear box close by...............:D I am defiantly a "butterfingers"
 
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#18
I've got them at Repco and other parts shops in the past. the same seals are used in a few different cars. You do need to get some one who will search the stock though...I have them but the box is currently too deep to get at. i'm taking a load of household stuff up to the new shed tomorrow and next trip will be the excess from the storage.
 
#19
thanks mike for the tips.
What exactly do I ask for at Repco, our local one has had a staff shakeup and all the knowledgeable ones have vanished, the tall thin middle aged lady was a wiz with hard to find
parts , even she has gone, probably retired to the gold coast to a pent house?
I guess there are only 2 rubber cups seals as per normal for master cylinders???
Peter
 
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