Can anybody help 17tTD 94 Astra, just had cambelt change, now brakes feel weird, sometimes they work, other times they just go hard and no braking effect, I suspect the Master Cylinder has gone, ro could it be jsut I need to bleed the system.
David
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I assume it's the GM engine model.
It's possible that a vacuum pipe has been accidently dislodged. At the end of the camshaft housing you'll find the vacuum pump. Follow the servo hose for about three inches and you'll see a small pipe that Ts off of it. Follow the small pipe until it disappears through the bulkhead. Remove the weather strip that goes right across the top of the bulkhead, then remove the plastic panel which gives access to the pollen filter. The vacuum pipe should be connected to the front of the air box. If it isn't that's your problem. Simply re-connect it.
You only have to lean on this vacuum pipe to disconnect it and that often happens when working on these models.
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Sure the vacuum pump hasnt failed, or belt to it come loose,or a leaking pipe to servo,or possible servo failure.
Doubt master cylinder
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Steve
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Yes that's also possible. He's just had a cambelt done hasn't he? It maybe that the vacuum pump drive has broken. That's not exactly uncommon either, but at least they are available seperately.....
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>>He's just had a cambelt done hasn't he?
Sorry Railroad,I took so long in typing you beat me to it,talking about another prob while typing
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Steve
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I think you will find that the vacuum pump for the brake servo is driven off the rear of the alternator (on this model) .If the cambelt has just been replaced ,then it is possible that the alternator drive belt has not been tensioned correctly.
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I think you will find that the vacuum pump for the brake servo is driven off the rear of the alternator (on this model) .If the cambelt has just been replaced ,then it is possible that the alternator drive belt has not been tensioned correctly.
That'll be the Isuzu engine. The GM engine's vacuum pump is on the back of the cylinder head. He doesn't say which engine it is, but 1.7DT is Isuzu and 1.7DTL is GM.
It's very easy to accidentally disconnect the vacuum pipe on the GM model. I've done it myself many times when doing many jobs.
The drive can break if the cambelt is too slack resulting in a vibration transmitting along the camshaft. Just like the distributor drive breaks for the same reason on petrol models....
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The drive can break if the cambelt is too slack resulting in a vibration transmitting along the camshaft. Just like the distributor drive breaks for the same reason on petrol models....
Not only the drive can break, but I've also seen a couple of snapped camshafts on these engines.
The first one I saw caught me out a little bit, it was a Manta. I took the cam belt cover off and asked my apprentice to spin the car over on the starter - everything looked OK. I turned the crank; all the marks lined up. Why wouldn't this car start?
I spent some time double checking that the spark and fuel were OK. On these, the distributor was driven off the front of the cam by a small toothed belt, so the spark, and spark timing were fine.
Eventually, I took the cam cover off, and initially didn't see anything wrong. All of the valves, springs, and rockers present and correct. It was only when I asked the apprentice to buzz the engine over again when I saw the camshaft remain still! It had failed imediately behind the first bearing. This was back in the time when these engines were notorious for munching through camshafts, and the cam which had failed was one of the cheapie non-genuine ones. Where there should have been a generous fillet between the bearing journal and the shaft proper, there was a sharp corner, from where the failure had initiated.
The second time I saw one, it didn't take me quite so long to find!
Number_Cruncher
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