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TC Kingpin replacement
Posted: Fri Feb 21, 2020 3:31 pm
by JohnW
In the near future I plan on replacing the king pins on my TC. I have done king pins on an MG B many years ago so not a complete novice on these matters, I just wondered if there is anything I really need to know before I start and where is the best place to buy the parts from (uk please)?
Thank you in advance for any advice offered.
Re: TC Kingpin replacement
Posted: Fri Feb 21, 2020 4:04 pm
by Steve Simmons
Kingpin replacement in a TC is easier than MGB. For one, the bushes are a straight 3/4" taper so no special reamer is required. I have purchased king pins and bushes from Roger Furneaux and the quality is quite nice. He also sells bushes and cotter pins. Many sources for the pins have the wrong heads on them but as I recall his are the correct type.
From memory, this is the sequence to replace a king pin...
- Remove the hub and bearings from the spindle.
- Remove the brake assembly and steering arm (steering arm shares lower backing plate bolts). You should be able to remove the brake without disturbing the hose and carefully set it aside.
- Remove the top dust cap.
- Remove the nut from the cotter pin and drive the pin out. This sometimes destroys the pin, so it's good to have a extra set on hand.
- Drive the king pin out, keeping a hand on the spindle so it doesn't fall and damage the threads.
- With a press (or socket and vise), press the old bushes out of the spindle.
- Press the new bushes in and ream to fit. I never assume a 3/4" reamer will be perfect, but prefer to use an adjustable reamer so I can creep up on it. A piloted reamer is a good idea, to ensure everything is straight. It's easy to ream too far, as a tiny cut can make a big difference. Having an extra bushing or two on hand isn't a bad idea.
- To quote the Haynes manuals, "installation is the reverse of disassembly".
- Replace the thrust washer and set vertical end float. If shims are necessary, place them on top. Let the thrust washer on the bottom take all the load.
The only tricky part is to make sure the cotter goes in flat against the cutout in the king pin. Sometimes the king pin doesn't rotate to "self align" with the pin. Because of this I like to lightly tighten the pin, then remove and make sure no burrs have been created on the mating surfaces. If all looks good then reinstall and fully tighten.
Hopefully I haven't forgotten anything. It's been a while but this thread is timely as I'm getting ready to do a set this month.
Re: TC Kingpin replacement
Posted: Sat Feb 22, 2020 5:11 am
by frenchblatter
Get kits from NTG 01473 406031 and talk to Linda. Tell her I sent you and said she'll give you discount.
The only problem you may have is if the cotter pins are siezed. I had to drill it out on one side, took ages, the other side took about an hour and a half. If you're anywheer near Barnsley, I'll come and give you a hnad if it helps
Re: TC Kingpin replacement
Posted: Sat Feb 22, 2020 5:13 am
by frenchblatter
I have a reamer you can use.
Re: TC Kingpin replacement
Posted: Sat Feb 22, 2020 3:23 pm
by JohnW
frenchblatter wrote: ↑Sat Feb 22, 2020 5:13 am
I have a reamer you can use.
Thank you for the very kind offer. I do have an expanding reamer and pilot that I bought ages ago just in case I might need it one day for this very job (makes a welcome change as I usually buy things that might come in useful one day but never do). Thank you again for the offer of help, alas I am almost at the other end of the country from you being near Wallingford in Oxfordshire.
Very jealous of the BDA in your 7, what a wonderful bit of design that engine is.
Re: TC Kingpin replacement
Posted: Sat Feb 22, 2020 3:24 pm
by JohnW
Steve Simmons wrote: ↑Fri Feb 21, 2020 4:04 pm
Kingpin replacement in a TC is easier than MGB. For one, the bushes are a straight 3/4" taper so no special reamer is required. I have purchased king pins and bushes from Roger Furneaux and the quality is quite nice. He also sells bushes and cotter pins. Many sources for the pins have the wrong heads on them but as I recall his are the correct type.
From memory, this is the sequence to replace a king pin...
- Remove the hub and bearings from the spindle.
- Remove the brake assembly and steering arm (steering arm shares lower backing plate bolts). You should be able to remove the brake without disturbing the hose and carefully set it aside.
- Remove the top dust cap.
- Remove the nut from the cotter pin and drive the pin out. This sometimes destroys the pin, so it's good to have a extra set on hand.
- Drive the king pin out, keeping a hand on the spindle so it doesn't fall and damage the threads.
- With a press (or socket and vise), press the old bushes out of the spindle.
- Press the new bushes in and ream to fit. I never assume a 3/4" reamer will be perfect, but prefer to use an adjustable reamer so I can creep up on it. A piloted reamer is a good idea, to ensure everything is straight. It's easy to ream too far, as a tiny cut can make a big difference. Having an extra bushing or two on hand isn't a bad idea.
- To quote the Haynes manuals, "installation is the reverse of disassembly".
- Replace the thrust washer and set vertical end float. If shims are necessary, place them on top. Let the thrust washer on the bottom take all the load.
The only tricky part is to make sure the cotter goes in flat against the cutout in the king pin. Sometimes the king pin doesn't rotate to "self align" with the pin. Because of this I like to lightly tighten the pin, then remove and make sure no burrs have been created on the mating surfaces. If all looks good then reinstall and fully tighten.
Hopefully I haven't forgotten anything. It's been a while but this thread is timely as I'm getting ready to do a set this month.
Thank you
Re: TC Kingpin replacement
Posted: Sun Feb 23, 2020 12:09 am
by frenchblatter
John, the car is going up for sale in the spring. I'll miss it, 0-60 in 3.2 secs. I just upgraded my Elise to a 220 sport, 0-60 in 4.2. I may go for an Exige when the 7 is sold, the 350 does 0-60 in 3.7. You just cannot have enough power, as long as it's a lightweight car
Re: TC Kingpin replacement
Posted: Fri Mar 13, 2020 9:33 am
by Eric Worpe
Hi John,
The king pins sets available from most retail outlets are about 0.5 thou. undersized. Doesn't seem much, but the slight rocking of the loose king pin results in the axle eyes becoming worn. This is a difficult and expensive issue to sort out. You cannot rely on the cotter pin countering any rocking due to its position at the fulcrum of the king pin. Measure your replacement king pins accurately and reject them if undersized.
Re: TC Kingpin replacement
Posted: Fri Mar 27, 2020 2:43 pm
by Warmuthb
King pin bushes should be honed for a proper fit. Reamers, while they will suffice leave highs and lows. A honed fit is much better for longevity.