A few issues, brakes, ac, etc, could use some feedback
05-03-2018, 09:47 PM
#1
Rennlist Member
Thread Starter
A few issues, brakes, ac, etc, could use some feedback
1982
Ok, shaking this car down...have some issues and would like some input please:
1) brakes: seemed a little squishy on the first couple runs...then sitting at idle in my driveway,foot on brake, the pedal suddenly dropped to floor and the warning lights started flashing. I released and pumped, and they grabbed good again, lights still flashing. Took a couple test drives, and the brakes are working, but a bit spongy.....then tonight, sitting in my driveway again, foot on the brake, pedal suddenly dropped to floor again. Released and pedal came up. Pressed again, and pedal is firm again. Any ideas/ thoughts on what to check? I have new switches to mount on master, hope that will clear up the flashing. Seems like if the master was bad, the pedal would hit the floor all the time...but it only has done it a couple of times sitting at idle, the other times it held firm....weird
2) 2nd gear grinds: worked fine on my 3 test runs, never had any grinding, and I know the gear oil was hot. Tonight, took her out for a quick run..could not hit 2nd at all without it grinding on me...thought it was me...came home for about an hour, and took her out on a 10 mile run...couldn’t hit 2nd to save my life without a little grinding...thoughts?
3) center flap: will not open when AC control set to Auto or Bi....don’t even know where to start....
4) on test run yesterday, blower went bezerk..even with the switches all off and fan on lowest setting...I am guessing it is the “magic fan syndrome”...I will pull the resistor pack...isn’t there a new style? Price?
5) always getting heat into cabin from footwell, I am guessing the heater valve is leaking by. I have a new one. Do I need some sort of special sized heater hose? The “short hose”?.
thats it for now...the brakes and center flap are my biggest concerns right now....thanks for playing!
Ok, shaking this car down...have some issues and would like some input please:
1) brakes: seemed a little squishy on the first couple runs...then sitting at idle in my driveway,foot on brake, the pedal suddenly dropped to floor and the warning lights started flashing. I released and pumped, and they grabbed good again, lights still flashing. Took a couple test drives, and the brakes are working, but a bit spongy.....then tonight, sitting in my driveway again, foot on the brake, pedal suddenly dropped to floor again. Released and pedal came up. Pressed again, and pedal is firm again. Any ideas/ thoughts on what to check? I have new switches to mount on master, hope that will clear up the flashing. Seems like if the master was bad, the pedal would hit the floor all the time...but it only has done it a couple of times sitting at idle, the other times it held firm....weird
2) 2nd gear grinds: worked fine on my 3 test runs, never had any grinding, and I know the gear oil was hot. Tonight, took her out for a quick run..could not hit 2nd at all without it grinding on me...thought it was me...came home for about an hour, and took her out on a 10 mile run...couldn’t hit 2nd to save my life without a little grinding...thoughts?
3) center flap: will not open when AC control set to Auto or Bi....don’t even know where to start....
4) on test run yesterday, blower went bezerk..even with the switches all off and fan on lowest setting...I am guessing it is the “magic fan syndrome”...I will pull the resistor pack...isn’t there a new style? Price?
5) always getting heat into cabin from footwell, I am guessing the heater valve is leaking by. I have a new one. Do I need some sort of special sized heater hose? The “short hose”?.
thats it for now...the brakes and center flap are my biggest concerns right now....thanks for playing!
Last edited by AirtekHVAC; 05-03-2018 at 10:48 PM.
05-03-2018, 10:35 PM
#2
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1. Master cylinder....nothing else will do that.
2. Clutch is either not completely releasing or synchro bad in 2nd gear. Push down the clutch and see how long it takes before reverse can be engaged without grinding. You should only have to hesitate for a second or two. If it grinds after a couple of seconds, clutch needs some attention. If it drops right into reverse, you've got a bad synchro.
3. What year car? '78 different from '82.
4. Pull resistor and clean the contact points for overheating.
5. What year car? '78 different than '82.
2. Clutch is either not completely releasing or synchro bad in 2nd gear. Push down the clutch and see how long it takes before reverse can be engaged without grinding. You should only have to hesitate for a second or two. If it grinds after a couple of seconds, clutch needs some attention. If it drops right into reverse, you've got a bad synchro.
3. What year car? '78 different from '82.
4. Pull resistor and clean the contact points for overheating.
5. What year car? '78 different than '82.
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714 879 9072
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
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Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
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greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
05-03-2018, 10:52 PM
#3
Rennlist Member
Thread Starter
Thanks for for the reply Greg. I edited my post to include the year....
10-4 on the master
grinds after a couple secs to reverse.
1982
will pull resistor pack
1982
10-4 on the master
grinds after a couple secs to reverse.
1982
will pull resistor pack
1982
05-04-2018, 02:24 AM
#6
Pro
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Ron,
What Greg said.
1. M/Cyl is shot. replace it. I know it is painful.$$$
Do not understand why a rebuild kit is not available. Back in the day we just replaced rubber bits.
2. Dual plate clutch adjustment is no fun, but can be done. PITA. Search Rennlist.
3. Center flap, ck vacuum, use mityvac to see if actuator is working, ck hoses.
4. Take out resistor pac, adjust high overheat bypass spring. Call me for details. Magic blower syndrome
5. Put in a manual shutoff. Only have to operate twice a year. The plastic valves are ****. Even new.
My 928€
Dave
What Greg said.
1. M/Cyl is shot. replace it. I know it is painful.$$$
Do not understand why a rebuild kit is not available. Back in the day we just replaced rubber bits.
2. Dual plate clutch adjustment is no fun, but can be done. PITA. Search Rennlist.
3. Center flap, ck vacuum, use mityvac to see if actuator is working, ck hoses.
4. Take out resistor pac, adjust high overheat bypass spring. Call me for details. Magic blower syndrome
5. Put in a manual shutoff. Only have to operate twice a year. The plastic valves are ****. Even new.
My 928€
Dave
05-04-2018, 02:43 AM
#7
Rennlist
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What Jeff meant to say is that anything is possible, but no one should ever drive a car around with a known brake failure issue, until something is proactively done.
A master cylinder is pretty simple hydraulics. There"s a rubber cup that is on a piston which seals on the bore of the actual master. When failure is intermittent, a small chunk of debris (or sludge) gets under the lip of that rubber cup and instead of fluid being pushed by the cup, it leaks around the cup....the piston travels down the bore without moving any fluid. That dirt (or sludge) likely came out of your reservoir, when you bled the brakes. There's also the chance that that cup is damaged slightly.
Whenever we have a client tell us this has happened, we change the master cylinder, clean the reservoir, and bleed the system. 100% chance the problem is fixed.
There is the possibility that cleaning the reservoir and bleeding the system could possibly remedy the problem....but there is also the possibility that next week, you won't be able to stop and you run over someone's kid in the crosswalk.
The risk isn't worth the price of a master cylinder....
A master cylinder is pretty simple hydraulics. There"s a rubber cup that is on a piston which seals on the bore of the actual master. When failure is intermittent, a small chunk of debris (or sludge) gets under the lip of that rubber cup and instead of fluid being pushed by the cup, it leaks around the cup....the piston travels down the bore without moving any fluid. That dirt (or sludge) likely came out of your reservoir, when you bled the brakes. There's also the chance that that cup is damaged slightly.
Whenever we have a client tell us this has happened, we change the master cylinder, clean the reservoir, and bleed the system. 100% chance the problem is fixed.
There is the possibility that cleaning the reservoir and bleeding the system could possibly remedy the problem....but there is also the possibility that next week, you won't be able to stop and you run over someone's kid in the crosswalk.
The risk isn't worth the price of a master cylinder....
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05-04-2018, 03:07 AM
#8
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Puzzeling, as it is a dual master cylinder. Both should not fail at the same time. Dual tandem master brake cylinders have been mandated for years. If one fails, should still stop, indicator light should show, but pedal should never drop to the floor. This indicates a dual failure, so replace it before driving the car. At.all.
05-04-2018, 07:29 AM
#9
Rennlist Member
Thread Starter
Thanks for the input guys. MC now on the hot list, and she goes back on the rack:
the center flap pod works properly with mighty vac. It was rebuilt by me and tested before reassembling the center console. Not sure if whatever makes it function is working now.
the center flap pod works properly with mighty vac. It was rebuilt by me and tested before reassembling the center console. Not sure if whatever makes it function is working now.
05-04-2018, 11:27 AM
#10
Nordschleife Master
For the magic blower: Have you ever opened up the HVAC under the cowl?
I was getting this, and when I pulled off the rubber sleeve, I found enough dust, dirt and lint to make a 'dust sheep' (lots more than needed to just make a 'dust bunny').
I cleaned up the resistor pack, cleaned a lot of crud out of the ducting and off the front of the A/C evaporator(?), and put it all back together.
Huge improvement in airflow and the magic blower mostly disappeared.
Because the "0" position on the **** actually runs it at the slowest speed, and that is the highest resistance in the pack, I can still get the blower to pop to full for a few seconds every now and then. Mostly when sitting still, on a hot day, with a hot car.
Thread on how to, with pics and the 'string trick':
https://rennlist.com/forums/928-foru...ic-blower.html
I was getting this, and when I pulled off the rubber sleeve, I found enough dust, dirt and lint to make a 'dust sheep' (lots more than needed to just make a 'dust bunny').
I cleaned up the resistor pack, cleaned a lot of crud out of the ducting and off the front of the A/C evaporator(?), and put it all back together.
Huge improvement in airflow and the magic blower mostly disappeared.
Because the "0" position on the **** actually runs it at the slowest speed, and that is the highest resistance in the pack, I can still get the blower to pop to full for a few seconds every now and then. Mostly when sitting still, on a hot day, with a hot car.
Thread on how to, with pics and the 'string trick':
https://rennlist.com/forums/928-foru...ic-blower.html
05-04-2018, 07:39 PM
#11
Rennlist Member
Thread Starter
All right...master cylinder on the way....
resistor pack looks easy enough....
could the master issue be affecting the 2nd gear? It was shifting just fine 2 days ago....anyway, not too worried about this yet...
big help needed on where to start with the center flap....
thanks fellers
resistor pack looks easy enough....
could the master issue be affecting the 2nd gear? It was shifting just fine 2 days ago....anyway, not too worried about this yet...
big help needed on where to start with the center flap....
thanks fellers
05-04-2018, 10:39 PM
#12
Chronic Tool Dropper
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Air in the fluid to the clutch MC? They share a reservoir, so what's bad for one can easily be bad for the other.
Plan on a new blue hose, and reverse-bleed the clutch hydraulics when you bleed the brakes with the new MC.
Plan on a new blue hose, and reverse-bleed the clutch hydraulics when you bleed the brakes with the new MC.
05-04-2018, 10:56 PM
#13
Rennlist Member
Thread Starter
Thanks Doc. The PO replaced the clutch master and slave, and used the new black(blue) hose, and it has no miles other than what I have put on it....so I’m good with that.
i have reverse bled #30 with good results, and this car as well, and I think that might have been my downfall....not so much the reverse bleed, but the fluid in this car was milky, and I pumped in new fluid from all wheels and clutch, allowing it to overflow from the reservoir into a container. What I didn’t really think about was that crappy old fluid and who knows what crud...mixing with my new clean fluid....hence I probably killed my own master.
that said, I have ordered a new master, with new switches pre mounted. How do I remove the reservoir (already know how to clean it)? I have new gaskets for the reservoir to master, so I plan on doing it right. How would you recommend flushing the system out? Sacrificial oil from a new container and traditional bleed? I thought about using my small 1/2 cfm vacuum pump and rigging a catch can and hose, filling the reservoir and sucking from the bleed ports.
i have reverse bled #30 with good results, and this car as well, and I think that might have been my downfall....not so much the reverse bleed, but the fluid in this car was milky, and I pumped in new fluid from all wheels and clutch, allowing it to overflow from the reservoir into a container. What I didn’t really think about was that crappy old fluid and who knows what crud...mixing with my new clean fluid....hence I probably killed my own master.
that said, I have ordered a new master, with new switches pre mounted. How do I remove the reservoir (already know how to clean it)? I have new gaskets for the reservoir to master, so I plan on doing it right. How would you recommend flushing the system out? Sacrificial oil from a new container and traditional bleed? I thought about using my small 1/2 cfm vacuum pump and rigging a catch can and hose, filling the reservoir and sucking from the bleed ports.
05-07-2018, 12:16 AM
#14
Rennlist Member
Thread Starter
Well, took care of the magic blower. Removed the resistor pack. It is very old looking, and does not have the “cage” around it, like in the pics I’ve seen.
sanded the 1 contact, soaked in deoxit, soaked the connector, plugged it all up...so far, working.
i don’t seem to have any vacuum at the solenoid pack behind the dash....where does it come from? Also found that my heat valve was bad. Replaced with a new one, and strapped it shut...it’s summer now...
New master should be here Wednesday.
AC system was flat. Pressurized with dry nitrogen and leak checked...solid. Evacuated system an d vacuum held at 30microns for an hour. Pulled triple evacuation, using r22 to break vacuum. Final vacuum, allowed to run 2 hours. Recharged with R-12...cooling quite well. Compressor seems solid. I will recover the charge later and replace the drier and recharge again with virgin gas.
sanded the 1 contact, soaked in deoxit, soaked the connector, plugged it all up...so far, working.
i don’t seem to have any vacuum at the solenoid pack behind the dash....where does it come from? Also found that my heat valve was bad. Replaced with a new one, and strapped it shut...it’s summer now...
New master should be here Wednesday.
AC system was flat. Pressurized with dry nitrogen and leak checked...solid. Evacuated system an d vacuum held at 30microns for an hour. Pulled triple evacuation, using r22 to break vacuum. Final vacuum, allowed to run 2 hours. Recharged with R-12...cooling quite well. Compressor seems solid. I will recover the charge later and replace the drier and recharge again with virgin gas.