« August 2023 | Main | November 2023 »
Completed the RH control arm/swivel pin rebuild. Stripped undercoating from inner fender. Applied red top coat to inner fender.
Basic Wheel Bolt Information:
Why do I need to measure my lug bolts with non-stock (aftermarket) wheels?
Unless specifically mentioned from the manufacturer that OEM wheel bolts can be used with your after-market wheel, it’s
important to always re-measure the lug bolt length. Some aftermarket wheels will have a thicker mounting pad (surface of the wheel that mounts against the hub of the vehicle). If that is the case, the stock wheel studs may be too short for the threads to pull properly. You need at least 9-10 engaged threads, (minimum).
Another "Rule of Thumb" to calculate thread engagement is to multiply the lug's threaded diameter by 1.5. For example:
3/8" x 1.5 = 9/16" length of engagement
9/16" x 24 TPI = 13.5 threads
In my case, after measuring the stock lug's exposed threads, extending through the hub/drum, and subtracting the wheel mounting pad, I had 9/16" of engaged threads. Still, that seemed to be on the "light" side of things to be safe with the 5' x 13' Minator wheel and 175 x 70 13 tire combination.
Extended Wheel Lugs and Verifying Engagement
This is an excerpt from the MG-Cars.info forum:
"The minimum required length of thread engagement is dependent on the relative strength of the male and female thread components and whilst the stud is usually good, unfortunately the same cannot be said for the nuts where it is possible that a much reduced strength of material has been used. In the limit, the bolted connection should should fail by tension in the stud and not thread stripping in either component. A further allowance should also be made in respect of thread wear that is far more likely to occur in wheel bolting than any other connection on the vehicle due to their more repeated use however caution must be used as thread lubricants may significantly reduce friction to result in failure due to excessive loading even at the stipulated tightening torque value. Better to only lightly oil threads and to replace, primarily the nuts, every few years or around 10/12 torque tightening operations."
"Scarlet's" Specific Wheel/Bolt Information:
Extended Wheel Stud length = 3/8-24 UNF x 2" (50mm)
Minator chrome wheel nuts = 3/8' - 24 with 1 3/16" threaded closed end nut
Minator 5' x 13" Spoke Alloy
The Minator Alloy wheel is based on the design made popular in the USA by Panasport. My Minator version is made by "KN" in the UK.
After ALL of my measuring and test-fitting, I still wanted to be sure that the lug was not bottoming out on the closed-ended acorn nut and that the nut was fully seated into the Minator wheel. My solution was to coat the cone-shaped base of the Minator lug nut with paint from a Sharpie paint pen. I then mounted the wheel to the hub/drum/wheel combination and properly torqued all of the nuts to 46 ft. lbs. (per factory specs ). As noted in the pictures above, when I removed the painted nut, all of the paint had been scraped/transferred to the base of the wheel. * Some vendors recommend 38 ft. lbs. for Minator wheels.
Conclusion: The Minator wheel, lug nut and front drum brake combination works fine with an Extended Wheel Stud length = 3/8-24 UNF x 2" (50mm)
References:
Sprite & Midget Tire Sizing and Wheel Selection
https://youtu.be/OSAHizphvWc?si=xYtgXomGMIcSQKuD
DIY: How to Calculate Lug Stud Length
https://www.youtube.com/watch?v=Hcc_ncnxzL8
Completed the control arm/swivel pin rebuild. Stripped paint from battery box, inner fender and front frame. Sanded all engine bay surfaces.. Measured 1959 cast wheel drums and set brake shoes to fit. Test fit new extended lug bolts Remove steering rack Remove exhaust down pipe. Remove steering column. Continue cleaning RH brakes & suspension Reorder extended lug boltsI’m returning to work this week on Scarlet’s (1959 Austin-Healey “Bugeye Sprite) front suspension and brakes. In Pt. 1 Renovating Scarlet's Front Suspension, I removed the springs, shocks, control arms, kingpin and steering rack. It’s taken a significant amount of time to disassemble, clean and paint the various components in anticipation of their rehab and rebuild.
To make some space on the workbench, I’ve decided to complete the assembly of the right-side brakes and control arm/kingpin assembly. Once complete, I can clean up my workspace and move on to the left-side components.
I previously ordered a swivel pin repair kit (264-185) from Moss Motors. The kit included new swivel pins, fulcrum pins, bushing, washers, shims etc. As soon as the kit arrived, I took inventory of the parts as there are some pretty tiny bits and pieces that would not be easy to source locally should they be missing.
Learning from others, I put the three cork washers into a plastic baggy filled with oil. Others have complained that trying to mount “dry” cork washers would result in them splitting during the mounting process.
As explained in Part 1, I encountered difficulty in removing the fulcrum retaining pin and the fulcrum pint itself. Thankfully, the repair kit included those parts. Before installing the fulcrum pin, I coated the threads with Permatex anti-seize copper grease and coated the center portion of the pin and king pin with red grease.
There’s a small lip in the inside of the control arm, where the fulcrum pin resides, that will help locate the oil-soaked cork washers. The cork seals are there to help retain grease, pumped in from the end of the fulcrum pin. There must be some long-standing engineering reason for the use of cork? I would think that a rubber/poly-type seal would provide a better seal and be longer lasting.
With the fulcrum pin inserted through the control arm and the bottom of the swivel pin I was able to insert the wedge-shaped locking pin, making sure to insert it from the top (nut and washer on the bottom).
The Restoring Sprites & Midgets book by Grahame Bristow, (page 38) provides some excellent tips on assembling the swivel pin (kingpin). Below is an excerpt from page 38:
"Assembling the Kingpin:
1. fit a new O ring into the base of the stub axle, note that it has a circular cross section, the upper seal (which fits under the trunnion) has a square cross section.
2. Locate the dust tube and spring assembly. Smear some water repellent grease onto the kingpin and then fit into the stub axle.
3. Fit the upper O ring, thrust washer, shims and top trunnion. This is best done with the assembly mounted in a vice. Firstly, put on some of the shims, fit the trunnion and rubber seal and using the old nut tighten down the trunnion.
If the assembly locks, add more shims. If the assembly is loose and the stub can be felt to move up and down on the king pin, remove some shims. When there is slight resistance, you've got it right."
A couple of notes from my personal experience:
Roger Williams said on the Austin Healey Bugeye Frogeye Sprite 1958-1961 Facebook forum:
”I have been working on sprites for 45 years. The first time I rebuilt a front end I replaced the bushes without checking for wear and had to ream them to fit. The second time and all times after that, I installed the spindle over the new king pin and found it to fit perfectly. It turns out that there was no wear on the bushing. It is the kingpin that wears. I have not found a worn bushing in a spindle ever. Your results may vary.”
Kenith Smith, on The Austin Healey Experience forum posted his experience in 2015:
”Peter C at World Wide Imports http://nosimport.com/ will ream and size the bushings and fit to the swivel pin. I sent to Swing Axle, Swivel pin, and all of the rest of the piece parts from the Major Suspension Kit to Peter C. His guys reamed the bushings and set them all up for clearances so all I needed to do was bolt the assembly to the wishbone and reassemble. Cost about $50 plus postage and turned around and going back to me the same day”.
With the swivel pin and stub axle assembly completed, I was able to reinstall the previously restored brake backing plate, shoes and cylinders. With the assembly still on the bench, I greased the swivel pin’s zerk fittings using my new LockNLube grease coupler.
The Restoring Sprites & Midgets book by Grahame Bristow on page 197 suggests fitting the stub axle and control arm (wishbone) to the car separately due to its weight. That would require fitting the swivel pin’s cork washers (personal experience #1) while on the ground. Uggggg! I’m going to try suspending the stub axle/control arm assembly from the damper and then mounting the rear of the control arm to the frame. That seems far less “fiddley” to me. If it doesn’t work out on the left side, I can try Mr. Bristow’s method on the right.
Conclusion: To do it right, a front end rebuild is probably one of the more expensive parts of the mechanical restoration phase, after an engine rebuild. My thinking is to do it right and enjoy a safer and better handling Bugeye for years to come. Part 3 of this series will be delayed as the engine bay MUST be refreshed and painted before I can re-install the front-end suspension.
Here are a few of the online resources that I used in preparing for my project:
A detailed look at how to disassemble a Frogeye Sprite's front suspension -Econobox - Bugeye Build Episode 22
Front suspension on MG Midget explained (Worn bushings & parts) – John Twist – Episode 203 MG Tech
Front suspension rebuilt by a newbie – Keith Smith – Austin-Healey Experience – Episode “Start-Stop”
Kingpin Rebuilt (Rubber Seals) - Front suspension rebuild : MG Midget Forum : The MG Experience
Scarlet, the 1959 Austin-Healey Bugeye Sprite, retains her original specification drum type brakes on all four wheels. There's a lot of controversy as to their effectiveness and many have converted their early sprites with disc brakes that came standard on the later Sprite and Midget models.
Scarlet's brother, Wally, has had that disc brake conversion which is certainly consistent with his larger 1098cc engine and 3.90 final drive ratio. That combination affords him a better highway cruising speed but would result in more demands on the braking system, due to speed.
Assuming tire size of 155/80 13 (per Gerard at http://gerardsgarage.com/ )
At 65 MPH with a 3.9, your RPM would be 3736
At 65 MPH with a 4.22, your RPM would be 4042
At 3600 RPM with a 3.9 your speed would be 62.6 MPH
At 3600 RPM with a 4.22 your speed would be 57.9 MPH
Scarlet, on the other hand, retains her original spec'd 46hp 948cc engine and (presumed at this stage) 4.22 final drive ratio. While the 3.9 diff will lower the highway rpm, it will also slow acceleration, thus making in town driving a little sluggish. Considering the type of driving she'll most likely be doing, the 4.22 final drive and drum brakes should be adequate.
Back to the project at hand . . .
With Scarlet up on jack stands, I've pulled all of the wheels and drums from the brakes. After giving them a quick clean-up, I thought that I'd simply take them to one of the local parts suppliers or auto repair shops and have them perform a light turn to give them the best surface going forward. Turns out that NONE of the folks in town were equipped to deal with 7" brake drums. Given that all modern cars are equipped with disc brakes and drum brakes have become much larger, that only makes sense. Also, the cost of replacement drums are relatively inexpensive in relation to the overall cost of the brake service.
Still, I wanted to see if I could retain the original drums, if possible. The Restoring Sprites & Midgets book by Grahame Bristow, (page 73) provides some good advice on "Making Better Brakes": "In many cases braking problems are caused by wear and tear rather than the system not being up to the job." Given that advice I've made the decision to completely overhaul the braking system, from the new master cylinder to the all new shoes, wheel cylinders, hoses, springs, etc. with the exception of the drums themselves.
With that in mind, I went in search of some advice and specs Bugeye brake drums. It's common knowledge that Bugeyes were originally equipped with 7" drums on all four corners. A quick look at replacement drums on the Bugeyeguys.com site reveals that the inside diameter of new drums is 180mm, or 7 inches. I didn't find a "definitive" source on what the maximum inside diameter or brake shoe thickness should be. There have been some forum discussions suggesting that 30 thousandths over is "marginal" and that 40-60 would time to source a replacement.
How do I measure brake drums?
So just how big ARE my drums? My first inclination was to grab a metal ruler, span it across the opening, and take a measurement. But would that give me an accurate measurement of the actual braking surface? I don't THINK so! How do other folks measure brake drums in this modern world of disc brakes? A search on the Internet, and of course Amazon) revealed a simple and inexpensive product that would do the job!
The Westward Brake Resetting Gauge filled the bill for my project. The GoVets site has a good set of specifications for the Westward Gauge.
Let's take a look at the drums!
As previously mentioned, I've cleaned the drums, so now is a perfect time to inspect them and investigate those mysterious stampings on the inside casting. It turns out that two of the drums appear to be original to the vehicle as they include a "59" casting and Scarlet was built in 1959. They also include the MOWOG casting and the number "177". What could THAT mean?
There are conflicting opinions on the Sprite forums on what the 177 casting number could mean. The common consensus is that the drum size is cast into each drum. Where the confusion (at least on my part) is if that number represents the original size or maximum diameter the drum can be turned. Using an Internet conversion utility, I found that 7.00 inches = 177.8 mm = 17.78 cm. To me, that seems to confirm that the 177 casting number. most likely represents the original diameter.
Based on that, and conventional wisdom that 30-thousandths over still represents a usable drum, I went back to the online calculator. I found that 7.30 inches = 7 5/16 inches = 185.4 mm = 18.54 cm.
Conclusion: A drum measurement between 177.8 and 185.4 cm would indicate a usable drum and could still be turned, if necessary, in the future.
Renovating Scarlet’s Front Suspension – Control Arm, Kingpin Assembly & Shocks
Most of my stories about Scarlet, the 1959 Austin-Healey “Bugeye” Sprite begin with the statement: “I plan to repaint the engine bay . . “ and this one is no different. With the Bugeye up on jack stands and the wheels off, I began removing all of the engine’s accessories (starter, generator, radiator, etc. ). The final step was to inspect the right (passenger) side front suspension prior to removal.
One of the first things that I noticed was that the rubber coil spring buffer had fallen and was resting on the bottom spring tray. These buffers are there to prevent the coil spring suspension from bottoming out so I wanted to get it reinstalled. So, the spring had to come out!
With the spring out I was able to inspect the upper cone-shaped spring mount located under the shock-absorber mount. It was quickly evident that water had gotten in that cone and rusted out the mounting hole to the point that the rubber spring buffer had simply fallen out.
With the spring’s tension no longer there, I noticed the A-Frame (wishbone / control arm) bushings were completely perished and that meant the front suspension was coming out!
Here's what I did to take it apart:
In anticipation of issues removing the control arm, I sprayed lots of lube in all over the bushing area. Here’s where it pays to be patient and let the penetrant do its work. Forum advice is it will probably be totally rusted together a that a Sawzall may become your best. There is room in there for a blade and it’s possible cut the mounting bold without hurting the suspension mountings or the wishbone.
I was lucky and managed to drive out both of the control arm’s mounting bolts. That’s pretty amazing, considering the condition of the fulcrum bushing in the control arm. As noted above, the control arm bushings were knackered to the point the only the metal bushing inserts remained. She must have had a tendency to clunk, shake and wander all over the road at any speed.
Tip: Prior to cutting it apart, check the kingpin (swivel axle) for movement front to back. The pin should be free to rotate on the same axis as the fulcrum pin but there should be no front to back movement. Scarlet's kingpin was thankfully in good shape.
I carefully examined the control arm for cracks and tears around the mounting holes for the metal bushings. Again, to my astonishment, they were in remarkably good condition considering that all evidence of the “rubber” bushings was non-existent.
I put the control arm on the bench and in a vise and began the process of removing the swivel axle pin. A wedge-shaped swivel locking pin locks a flat side against a similar flat on the side of the fulcrum pin. As the front suspension goes up and down, the fulcrum pin now solidly connected to the swivel pin, rotates on the metal threaded bushings at the end of the control arm.
The manual says to simply unbolt the locking pin and drive out the swivel axle pin. More commonly it’s likely it will be totally rusted in place, or in my case, a previous owner had welded the pin on both ends! Using a small grinder on my Dremel, I was able to grind down the welds and then punch out the remains of the licking pin and remove the fulcrum pin.
The LH control arm had just the opposite issues! In that case, the locking pin remained intact and unbolted and was driven out with ease. Smooth sailing from there, right? Wrong again! This time it was the fulcrum pin that had wouldn’t release. I applied generous amounts of WD-40 and let it sit overnight but it would still not unscrew.
Thankfully, I have a nearby friend with skill, knowledge and tools to “persuade” most any metal object. A cutting wheel in a right-angle grinder managed to cut through the fulcrum pin and we managed to free most of it from control arm. However, at this point, the rest of the fulcrum pin still remained frozen in the control arm . Arrrrrrrgggg!
The solution involved welding a bolt to the end of the frozen fulcrum pin so that we could simply unbolt it. Not so fast! It seems, that was the original issue. We ended up getting out the oxy-acetylene torch and applying heat and torque to the pin and eventually it was extracted.
With the offending fulcrum pin removed, I worked in a new replacement pin and was pleased to confirm that everything was in alignment and that the threads were sill in good shape. This is important because both sides need to be exactly aligned.
Tip: It was at this point (both sides of the front suspension removed) that I came to the conclusion that it would have been more economical, certainly from a “time” standpoint, to simply have purchased new control arm pre-drilled for sway-bar mounting. Removing, cleaning, painting, etc. can take days! The front suspension control arm is $170 from Bugeyeguys.com
Part 2: or Renovating Scarlet’s Front Suspension – Control Arm, Kingpin Assembly & Shocks - Will continue with restoring the king pin assembly, the brakes and reinstallation of the entire assembly.
