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Poor timing!

Z

zcacogp

Active member
Giles, A thread entitled "Poor Timing" on here could mean any one of several things, including that your cam belt has just broken. So things could be worse ... Scratching my head, the only thing I can come up with is that some flaps in the heater system are powered by vacuum lines. This diagram (and labels) may be helpful;
hvac-3.jpg
Number 5 is "Vacuum line for heating valve". This may be a common line with the brake vacuum assist line (they may T-off each other somewhere). If so, a broken line somewhere or split hose may explain the symptoms you have. Keep us posted. And I hope the wedding goes well. I've been Best Man three times and both loved and hated each wedding in equal measure. Oli.
 
I've got to drive to Torbay this afternoon (around 2 hours) for a wedding, where I'm a best man. So I set off to work, everything normal. About halfway there, suddenly the brakes feel unresponsive, and the ventilation system will only blow hot air on all settings! [:mad:]

Feels like the brake vacuum assist has failed, and I guess the hot air only is the little clip in the dashboard. But of all the timing! It has to break when I've got a long drive on a hot day and need to be in decent shape at the end!

Does anyone know of a link between the hot air and the brake vacuum assist? Seems odd that they both go at the same time...

Cheers.
 
Thanks Oli True, when you put it that way, it could be worse! At least I can drive it, albeit slowly and carefully, and while slowly cooking myself! Interesting that the vacuum system powers some heating flaps too, that might explain it. If I get a chance (unlikely!) I'll have a look at the vacuum lines this weekend. It's my first wedding as best man - as you say, part love and part hate! I'll be glad when it's over... Thanks for the diagram. Presumably as number 7 is the right footwell flap, I'll find all that lot somewhere near the back / bottom of the block?!
 
Giles, Sounds like you are on the case, but the big black thing pictured is the HVAC (Heating Ventilation and Air Conditioning) unit, in the middle of the dashboard. The picture shows it from the RHS, so driver's side. The vacuum pipes leave the engine bay under the scuttle cover and go through into the passenger compartment there, so you should be able to trace them back to see if there are any problems. Yes, it is interesting that some of the system is powered by electric motors and some of it by vacuum. I can't understand why they would design it like that, but I can't understand quite a lot of the design of the 944 anyway! Oli.
 
This is an oval dash car? If so, as Oli says, split vac line (or fallen off) somewhere. I'd start with the hose to the brake servo, as a split in one of the very small ones wouldn't be so bad. there's also that odd black canister that is a vac reservoir isn't it?
 
Thanks. Yes, it's oval dash. And yes, I think one of the brake hoses is the likely culprit as I was in the middle of braking when suddenly the brakes got less efficient, and I think that's when the heater started to blow hot too. I'll see if I can inspect the vac lines, and hopefully it'll be obvious. Wish I'd packed some dirty clothes now!
 
Look on the bright side - you are going to be with some of your best mates who will want to help you, and will have nothing to do but drink beer this evening. Sounds like an ideal situation - and the weather is due to be warm as well! [:)] Oli.
 
ORIGINAL: zcacogp Look on the bright side - you are going to be with some of your best mates who will want to help you, and will have nothing to do but drink beer this evening. Sounds like an ideal situation - and the weather is due to be warm as well! [:)] Oli.
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Some of my best mates who will be happy to mock my poor old Porsche, and probably be too smart to help! (Dressed smart that is, though also too sensible to help perhaps!) And there's a wedding rehearsal and meal tonight and wedding all day & night tomorrow! And the warm weather means that I will cook in my black car with lots of glass and a heating system stuck on hot!! [&:] Haha! Oh well.
 
I can only concur with the other opinions that you should look into something common to both sytems and that has to be that you have an air leak into the vacuum system. If by unresponsive you mean requiring more pressure on the brake pedal, almost to the extent of using both feet then you have lost the servo assist and to be honest and with the greatest of respect it may be a foolhardy decision to drive the car without the servo assistance if that is the case. The least you can do tonight is to have a look for obvious split pipes.
 
ORIGINAL: 924nutter I can only concur with the other opinions that you should look into something common to both sytems and that has to be that you have an air leak into the vacuum system. If by unresponsive you mean requiring more pressure on the brake pedal, almost to the extent of using both feet then you have lost the servo assist and to be honest and with the greatest of respect it may be a foolhardy decision to drive the car without the servo assistance if that is the case. The least you can do tonight is to have a look for obvious split pipes.
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Yes, that's the symptom. I tested it out on the way to work, and it did still stop OK (only needing one foot on the pedal), just not quite as handily as usual. But you're right of course - if it gets scary, I'll get breakdown recovery to take me down there.
 
That's a fairly extreme point of view John; once upon a time there were no such things as power-assisted brakes, and people managed cars just fine back then. Indeed, London busses in the 1960's had brakes which were so heavy you would typically have to put both feet on the pedal and lever yourself against the seat to get any reasonable degree of retardation. Giles has a car with perfectly adequate brakes, but no power assistance. Oli.
 
Cheers oli Doing ok so far, slow and steady. And I'm stopped while typing this! Can anyone recommend a 944 garage in torbay?
 
No one that far south but depending on how far you've got on your journey Crispin Manners - Oaktree Garage, Newton Poppleford, Sidmouth, Devon Tel. No: 01395 568498 Andy Moss – Honiton, Devon Tel. No: 07762 244477 Martin Reed - Cladivan, Barnstaple, North Devon Tel. No: 01271 375696 Andy Moss is a nice chap - did a PPI on my S2 (and had done loads of work on it) I'd try him first
 
ORIGINAL: zcacogp That's a fairly extreme point of view John; once upon a time there were no such things as power-assisted brakes, and people managed cars just fine back then. Indeed, London busses in the 1960's had brakes which were so heavy you would typically have to put both feet on the pedal and lever yourself against the seat to get any reasonable degree of retardation. Giles has a car with perfectly adequate brakes, but no power assistance. Oli.
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And the assistance is relatively light on the 944 compared to say a modern audi. My old nissan patrol had a massive amount of assistance on the brake and clutch the clutch almost needed both feet with the engine off, the brakes I never tried moving but the pedal felt like someone had bult a brick wall under it and the steering felt like it was locked without power assistance
 
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