Rear flappy boxes
11-06-2013, 06:32 PM
#1
Three Wheelin'
Thread Starter
Rear flappy boxes
Don't know their proper name (heat dump valves?) but I'm referring to the two alloy boxes that sit at the other end of the orange heater hoses that attach to the heat exchangers.
How loose should the internal flap inside them be? I have them off the car and although the flaps will move when pressed with fingers, its certainly not loose enough to move when shaken about. I can't see that the blower would be able to generate sufficient pressure to move them.
Thanks
How loose should the internal flap inside them be? I have them off the car and although the flaps will move when pressed with fingers, its certainly not loose enough to move when shaken about. I can't see that the blower would be able to generate sufficient pressure to move them.
Thanks
11-06-2013, 07:39 PM
#2
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They should move by turning the housing. Some where in the net you can find a workaround. You just have to drill the rivettes to seperate the two halfs. Then you can fix it.
Good luck!
Good luck!
11-07-2013, 11:22 AM
#3
Nordschleife Master
They should be so loose that you can hear clink, clink when you shut a door due to the air pressure change moving them. Saying that, I don't think mine move that freely but my heating system appears to work well.
11-07-2013, 04:00 PM
#6
Three Wheelin'
Thread Starter
Thanks guys. I split both the boxes open this eve and it isn't looking good.
The flap has a pivot pin welded to it which is supported both ends with plastic bushes recessed into the Walls of the housing.
One end of the pivot on each flapper has rotted to nothing, and the corresponding bush is munched.
I'll come up with something to sort them out
but it's far from an interesting/exciting problem to solve.
The flap has a pivot pin welded to it which is supported both ends with plastic bushes recessed into the Walls of the housing.
One end of the pivot on each flapper has rotted to nothing, and the corresponding bush is munched.
I'll come up with something to sort them out
but it's far from an interesting/exciting problem to solve.
11-09-2013, 10:55 AM
#7
Three Wheelin'
Thread Starter
Right'o, my non flappy, flappy things are now sorted. Here's what I did.
The flappers pivot on a steel pin that protrudes from a chunky alloy casing and then spot welded to the flapper (over the top engineering?). This is what the 'good' ends of the pivot pin look like.
This is what the 'bad' ends look like. The pin has rusted away resulting in it just binding.
Here you can see the chunky casting that houses the steel pivot pin.
A quick stroke of the grinder on the spot welds had them separated.
The protruding ends of the steel pins are approx 4mm OD so I cut two of the correct lengths from a piece of 4mm aluminium bar.
The pins where then epoxied to the flappers ensuring they stood proud of the surface by 2mm as they would have done in the old housing.
The ends of the pivot sit in tiny plastic bushes recessed into the wall of the heater box housing. On closer inspection I decided not to reuse them and lifted them out since they were furred up.
Now I don't believe the bushes are available so instead I filled the recesses with more epoxy (JB weld) and them drilled the correct size hole for the pivot.
All that remained was to reassemble with 3 pop rivets into each housing that had to be drilled out to separate the unit.
Both flappers now move about very freely, and are hopefully a little more corrosion resistant now since there's no steel
The flappers pivot on a steel pin that protrudes from a chunky alloy casing and then spot welded to the flapper (over the top engineering?). This is what the 'good' ends of the pivot pin look like.
This is what the 'bad' ends look like. The pin has rusted away resulting in it just binding.
Here you can see the chunky casting that houses the steel pivot pin.
A quick stroke of the grinder on the spot welds had them separated.
The protruding ends of the steel pins are approx 4mm OD so I cut two of the correct lengths from a piece of 4mm aluminium bar.
The pins where then epoxied to the flappers ensuring they stood proud of the surface by 2mm as they would have done in the old housing.
The ends of the pivot sit in tiny plastic bushes recessed into the wall of the heater box housing. On closer inspection I decided not to reuse them and lifted them out since they were furred up.
Now I don't believe the bushes are available so instead I filled the recesses with more epoxy (JB weld) and them drilled the correct size hole for the pivot.
All that remained was to reassemble with 3 pop rivets into each housing that had to be drilled out to separate the unit.
Both flappers now move about very freely, and are hopefully a little more corrosion resistant now since there's no steel