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MG TD, TF Door Hinge Refurbishment
by
Roy Challberg
Summary
The original MG TD and TF "suicide" door hinges use steel pins making direct contact with the brass hinge material. When the pin starts to rust, the oxide acts as sandpaper and enlarges and elongates the holes in the brass hinge. As the holes enlarge, the doors start to sag.
The restored hinges are drilled and sleeved with bronze oilite* sleeve bearings and offer a very tight fit. The original steel pins are replaced with stainless steel shoulder bolts for a non-corrosive unit. These rebuilt hinges should provide years of easy, permanently lubricated, non-sagging door operation.
The original steel hinge pin is removed and the hinge is stripped of any paint. The pin holes are drilled out to 5/16" for both sides of the hinge. A 5/16" OD by 0.250" inner diameter bronze oilite sleeve bearing is inserted into the three hole positions. The aligning holes are then hand reamed out to 0.2502". A 0.250" diameter shoulder bolt is used as the new pin. The 18-8 stainless steel precision shoulder bolt is used instead of a common S.S. bolt because of the closer tolerances and machined surface.
Detailed Instructions
1. Remove the steel pin from the original hinge by using a file, hacksaw or cutoff wheel to remove the bottom end. A drift may be necessary to drive out the pin from the hinge holes.
2. Align the holes of each hinge half piece to be drilled by setting up the hinge piece loosely in the vice and by using either the ¼" drill or the ¼" reamer to check and self-align the hole for a straight cut. Tighten the vise for drilling.
Note: Both halves can be drilled at the same time if the halves can be clamped in the vise together and the alignment of the holes maintained. This is usually not possible and each half must be drilled separately.
3. Drill out the holes of both sides of the hinge. Start with a 9/32" drill (1/32" over the original ¼" hole) followed by a 5/16" hole (1/16" over). Make very small movements of the drill, allowing only minor material to be removed. The brass is very soft and the drill will grab the brass if too large of a metal removal is made.
4. Drive the 5/16" diameter bronze sleeves into the newly drilled holes. The sleeves are usually a tight interference fit. The drill press vise can be used to slowly drive in the sleeves. Make sure the ¾" long sleeve is fully seated in the middle piece. Make sure the ½" long sleeves are fully seated in the outboard holes. The ½" long sleeves will have to be trimmed with a hacksaw or cutoff wheel to fit the correct length. Smooth off all surfaces with a file.
5. Using the ¼" hand reamer, ream out all the newly installed bronze sleeves.
6. Put the two hinge halves back together and trial fit the ¼" stainless steel shoulder bolt through all the holes.
7. Remove the bolt and round off the top to resemble the old steel pin. You can fill in the Phillips head slots by TIG welding or some other type of permanent filler (e.g., J-B Weld).
8. Grind the six points off of the 10-32 stainless steel nut and install the nut on the shoulder bolt for the last time. Tighten the nut and check the swinging action of the hinge to make sure there is no binding.
9. Weld the rounded nut into place after first making sure of the direction of the bolt. The head of the bolt should be on the top of the hinge for either the left hand or right hand side of the car.
Another way to lock the shoulder bolt into place would be to cut off the end of the threads leaving about 1/16" and then flatten the end.
Note: Left hand hinges can be made right hand hinges by simply reversing the direction of the pin. The hinges with three mounting holes are used as top hinges while the hinges with only two mounting holes are the bottom hinge.
10. Remove any paint from the hinge with a wire brush, paint remover, or sandpaper.
Parts Needed and Source
The source for all these parts is McMaster-Carr (www.mcmaster.com). The part numbers are provided and the approximate cost. Some of the parts may be bought at your local hardware store and are marked as such.
|
Description |
Size |
Part # |
# per hinge |
Approximate Price |
| 18-8 stainless steel precision Phillips shoulder screw | 1/4" dia., 1-1/2" long, 10-32 threads | 94045A546 |
1 |
$6.20 each |
| SAE 841 Bronze Sleeve Bearing | For ¼" shaft, 5/16" OD, ¾" length | 6391K401 |
1 |
$0.75 each |
| SAE 841 Bronze Sleeve Bearing | For ¼" shaft, 5/16" OD, 1/2" length | 6391K127 |
2 |
$0.65 each |
| High-speed steel hand reamer, straight flute | ¼" dia., 2" flute length | 2989A15 |
1 (total) |
$35.00 |
| Stainless steel nuts | 10-32 thread | Hardware store or 91240A44 |
1 |
$0.70 each |
Tools Needed
Bench top drill press
Drill press vise
Pneumatic die-grinder or electric angle grinder with cut-off wheel
File
Punch for removal of old pin
TIG welder (or use substitutes as mentioned in procedure)
Photos of Hardware and Finished Hinges
Shoulder Bolt and Bronze Bearings
Refurbished Hinges
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