| Author | Message | ||
| dave handa (Davehanda)
Intermediate Member Username: Davehanda Post Number: 2135 Registered: 5-2001 |
Verell, Sell me one! You name your price, as I am certain it will be a work of art! Davfe | ||
| Verell Boaen (Verell)
Intermediate Member Username: Verell Post Number: 1312 Registered: 5-2001 |
Saw John's new screw at Steven's OCTOBERFEST. The new one has a significantly larger diameter thumbwheel (Easier to turn!). Also was almost 3x the length of the original. We decidded that John should thread a matching nut onto it, then cut the excess length off. Backing the nut off will cleanup any threads damaged by the cutting. I've got John's broken bleed screw. Think I'll get some lathe practice in by turning out a couple of them. | ||
| Verell Boaen (Verell)
Intermediate Member Username: Verell Post Number: 1270 Registered: 5-2001 |
Peter, Sounds like you missed the key point: Dissimilar metal Electrolysis The steel screw, the coolant, and the brass threads are a recipe for electrolysis driven corrosion. One of the pieces of metal is eventually going to get eaten away big-time. | ||
| Dr Tommy Cosgrove (Vwalfa4re)
Intermediate Member Username: Vwalfa4re Post Number: 1343 Registered: 5-2001 |
The second biggest problem with this screw is it popping off. Just when you think it is about ready to come off, it already did AND hid itself in the deepest darkest crevice of the front end. You finally find it 2 hours later after removing the left front tire, spare tire, battery, inner fender well, grill behind the headlight, part of the headlight, and heater air tube. Guess how I know this. | ||
| DGS (Dgs)
Member Username: Dgs Post Number: 426 Registered: 5-2003 |
The stock water pump bleed "valve" on my Alfa is just a half-slotted screw. But it's an aluminum screw, not steel. Actually, I was thinking in terms of a dremmel cutting wheel, rather than "filing" a slot into the threads. When doing any machining to a screw -- even just cutting it shorter, it often helps to thread a steel nut onto the screw, which can remove any oddities from the threads as you remove it, after the cutting and filing is done. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 557 Registered: 5-2001 |
DGS, One would have to be very carefull of filing a slot on the side of a screw to create a bleed channel. A slot edge or thread left unrounded, will turn the screw into a crude tap and may remove some of the softer brass and ruin the fit. | ||
| DGS (Dgs)
Member Username: Dgs Post Number: 424 Registered: 5-2003 |
An easy alternative to trying to drill a hole up the middle (for those of us who don't have a precision drill press) is to grind a slot down the lower part of the threads. Leave enough untouched thread to seal, then back out to let the air escape through the slot. But if the original is available from T.Rutlands for not much cash, why mess with it? | ||
| '75 308 GT4 (Peter)
Advanced Member Username: Peter Post Number: 3179 Registered: 12-2000 |
Guys, a simple O-Ring rolled up to the head of the bolt does more than enough sealing, don't bother with teflon tape... I know all about this, I busted mine earlier this year (nothing more irritating than breaking this stupid thing). Take that Allen-socket bolt, drill the necessary bleeding holes through it, use the O-Ring as I suggested and to top it off, pop a plastic knurled knob on the end of the bolt to make hand-removal/tightening possible. These plastic knobs I mentioned are available at hardware stores for under a buck... Cheap and WAY better than the original. | ||
| Skip Williamson (Darolls)
Junior Member Username: Darolls Post Number: 156 Registered: 7-2003 |
T. Rutlands has them, or did. Very inexpensive so check them out. | ||
| Dr Tommy Cosgrove (Vwalfa4re)
Intermediate Member Username: Vwalfa4re Post Number: 1342 Registered: 5-2001 |
Mine broke the same way back in 98. I had to make one myself. I even drilled the same holes in it. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 556 Registered: 5-2001 |
Thanks Verell, I found your discription of the drilled bolt but didn't find your picture of it, but I get the idea. You wrote that you drilled about a 3/32 axial hole up the center of the bolt and about 1/4 the way from the head you drilled an intersecting hole. | ||
| Verell Boaen (Verell)
Intermediate Member Username: Verell Post Number: 1267 Registered: 5-2001 |
Bill, A while ago I posted photos of my drilled thermostat bleed bolt. I understand that 911s use a bolt that comes drilled but is otherwise identical. BTW John, Bill's right on about corrosion. I wouldn't leave a steel bolt in there for more than a couple of months. His suggestion about teflon tape sounds like a good one also. | ||
| John Wise (Jwise)
Junior Member Username: Jwise Post Number: 70 Registered: 4-2003 |
Bill, teflon tape is a good idea. I already installed it with anti-sieze without any leaks. If it does leak, I'll try the tape. Verell, I figured you would chime in with a way to make one! I'll tell you folks, this man has two of every tool you can think of. Thanks for the info and the offer to help. I might have to take you up on it. I tried to clean off the oil we saw on the front of the block and it was dried and old. When I checked the problem area this weekend, no drips yet so I'm hoping to hold off on the major for a while. I'll give you a call this week to catch up and see how things are going. I'm trying to hook up with you guys this coming weekend at Steven's. Thanks again. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 555 Registered: 5-2001 |
John, The steel replacement should be fine for a while. Sealing and corrosion are a concern, but you could put a little antisieze on it. I don't know if the allen head screw will seal though. Maybe instead of the antisieze, a couple of wraps of teflon tape would seal and protect against galvanic corrosion. By the way, the radiator bleed screw is drilled to allow the release of air without removing it from the radiator, I wounder why the bleed screw in the thermostat housing is not the same design? | ||
| Verell Boaen (Verell)
Intermediate Member Username: Verell Post Number: 1263 Registered: 5-2001 |
John, if you can't find one, bring it over. We can get you fixed up. There are a couple of options: a) Braze it together, re-tap the threads, then re-drill the center hole. b) Make a new one. I've got some 11/16" brass rod. Would only take an hour or so to turn one out. BTW, still planning on doing that major? | ||
| John Wise (Jwise)
Junior Member Username: Jwise Post Number: 69 Registered: 4-2003 |
I was bleeding the system one last time after getting it perfect and the bleeder screw on the radiator snapped in my hand and proceeded to squirt hot coolant everywhere. My question- where can I find a replacement for this? I checked Ferrari UK and couldn't find it. I bought a 6 mm allen head screw for a temporary replacement until I can find the right part. Any harm having a steel screw in a brass radiator for a short time? Thanks folks.  |