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Front Big Brake Conversion

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M

MCS

Jedi Warrior
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Hello,

I need some help. I am trying to complete my Sprite big brake conversion.
So far I have the spitfire rotors installed and rebuilt MGB calipers installed. I have machined all the required areas and they do not bind. My problem is when I install the ball joints both wheels are sitting at aprox 1/2 inch of toe out. The ball joints are screwed in as far as they will go. I am using the recommend steering arm spacers from Mini mania. Here is a link.

https://www.spridgetmania.com/web/Item/HUF175/InvDetail.cfm

I rebuilt the rack at the same time, It is like I stretched the rack longer
Any ideas as to what I am missing. I have read that some guys just bend the steering arms out and do not use spacers.

Thanks Phil
 
Phil, can you turn in the inner tie rod ends any further?
 
I've used the big brake combo, it was invented for SCCA racng, but never the combo of the early rack, and normal outer tie rods. You may want to lose the steering arm spacer and see what you have then for alignment, they may very well be the source of your problem. These big brake adapter are made by Huffaker, who used a totally different set up on his steering racks and needed those spacer to make his rack set up work, I driven and prepped one fo his Spridget race cars, so I'm familar with his set up.
 
Whether the early rack or the later rack, if the steering arms are moved inward, the front end will toe out. The eary rack uses a 5/8" tie-rod end. These are bigger and bulkier than the later rack's tie-rod ends which are 1/2". The choice of wheel bearings affects the location of the disk brake rotor as well. The tapered roller bearings can move the rotor away from the tie-rod ends compared to the stock ball bearings. There are two sets of tapered roller bearings that can be used for the inner and outer bearing replacement. Don't have my Timken catalog handy or I could provide all four numbers. One set is the 30205/30303 pairing. The others are like 0797/0562. The second set's are the ones I am unsure of. I'll look tonight and see what the exact part numbers are and post tomorrow.

Back to the rack. When I ran the old rack setup on my RH drive FP Spridget, I used an adapter that allowed me to use 1/2 RH & LH rod ends for connection to the steering arms. I had to shorten the tie rod ends and rod end shanks to get enough adjustement.

I'm with Hap, the spacers seem to be the issue. I have typically used a couple of 3/8" flact washers in the past to get just enough spacing to not touch the Spitfire disk brake rotor.

Sounds like you might have to adjust things in a couple of places to get enough adjustment.

HTH, Mike
 
JP, Hap and Mike thanks for your help.


The ball joints are screwed in all the way.
I tried fitting the steering arms without the spacers, no luck. I then used washers , I needed an 1/2 of washers to clear the rotor.
The steering spacers are 5/8 thick. I measured the toe out, I need to shorten my tie rod ends by 1/2 and the ball joints by 1/2". This will make my wheels point straight like a nice set of ..... well use yur imagination.
Talked to an MGA guy he fit MGB brakes on his car and told me he cut his tie rod and ball joints by 3/4"

I spoke to Rob at Winners Circle, he told me they like to bend the steering arms using heat. That made me nervous, I would rather use a spacer. I just received from Winner Circle, there front sway bar and rear panhard the quality is excellent, great guys and very helpful.

I wish someone made shorter tie rods, makes me a little nervous cutting steering parts. After I cut the ends, there will still be at least 1 " of thread in each ball joint, I think the rule of thumb is at least the diameter of the thread, the tie rods are 5/8, so plenty extra.

The MGB brake conversion is a challenge, sure hope it works well, not sure if I would have done this, knowing what I now know.

Thanks Phil
 
Phil, I might still have my old tie rod ends if you want something to experiment with - let me know if you want me to look
 
Ok I solved the problem.
i cut 1/2 inch off of tie rod and ball joint. If I get to it tonight I will take a picture of MGB brakes with frontline suspension. Nice setup

Cheers Phil

Thanks for the offer JP, almost had to come by for Lunch today. Maybe by April my sprite will be ready for a road trip to YYZ
 
anytime - especially in that little rocket. Although, you got to stop customizing and start painting one day.
 
OH, I forgot to add, installing one of these set ups is a PITA, and no two go on the same way, but I guess you already know that now :smile: :smile:
 
Looks like you've got a success path forward. I went ahead and looked up the various Timken roller bearing pairs. The inner bearing cone is the key. It locates the hub/rotor in relation to the stub axle. Each of these bearing pairs has sufficient radius on the ID for the stub axle spindle. Occassionally, one will find a spindle that has a very large radius into the stub axle and some grinding will be necessary on the bearing ID to clear.

Inner Bearing Cone/Cup
X30205/Y30205 (+.049 further out from stock 205 ball bearing)
07097/07205 (+.0004 further out from stock)(Hardly a difference)

Outer Bearing Cone/Cup
X30303/Y30303
05066/05185

A couple of last minute things to note. 1) When using the 30205/30303 bearing sets, often the cotter key slot doesn't reach the hole in the spindle. Turn the nut down on a lathe to the necessary distance to obtain the proper alignment. Usually about 0.060 - 0.080". 2) The MGB brake calipers often don't center on the new rotor location. Correction requires the caliper mounting ears to be machined on the mill. A bit of a trick to hold the caliper for machining.

HTH,
Mike Miller
 
MGB brake conversion= very large PITA
I purchased the Winner Circle Timken roller bearings, no problems with the fit. I did notice that the rotor is not perfectly aligned in the caliper. The pads fit ok, nothing drags so I am thinking it should work. If not I have a note to mill the caliper ears. As JP states I need to stop modifying my car and focus on painting. I could buy two finished sprites with what I have invested, I have a problem.
Thanks for the help.
 
After 37 years of SCCA Club racing, I guess I'm just used to all the PITA's encountered over the years and it just becomes part of the process of installation. Over the years I started building/putting together all my own kits. Bought or borrowed WC, Huffaker or whomever's stuff and then copied, improved or changed to my way of liking. Front brake conversions, rear disk brake conversions, dual braking systems, tunnel exhausts, suspension stuff, just whatever was needed.

Good luck on your project and yes, start some painting. That is one thing I haven't ever tried. Maybe before I'm 6 feet under. One room of my rental shop was a paint room at one time.

Take care and have a great day,
Mike
 
I was going to do this conversion on my Spridget vintage racer but tried a new set of Brembo rotors and Green Stuff pads instead. Simpler, cheaper and surprisingly effective. Hauls my car down from 100 mph + (GPS numbers) to about 25 time-after-time on the BeaveRun back straight with no drama.
grin.gif


I tend to be a "late-braker", and pretty hard on brakes. Anyway, worked very, very well.....huge improvement over the old rotor/semi-metallic combo.

Now if I could just keep the oil off the rear brakes. :crazy:

I plan on using the same Brembo/Green Stuff combo on the A35 I'm building.
 
MCS said:
As JP states I need to stop modifying my car and focus on painting. I could buy two finished sprites with what I have invested, I have a problem.
Click to expand...

My name is John-Peter Smit and I am a Midget-oholic :crazyeyes:
 
MCS said:
I could buy two finished sprites with what I have invested,
Click to expand...

Oops, and of course we'll never tell AND I know where you keep the receipt book and I'll grab it and hide if necessary - that's what friends are for.
 
Hey JP,
You promised you would bury me with my receipt book if required
Phil
 
MCS said:
Hey JP,
You promised you would bury me with my receipt book if required
Phil
Click to expand...

Or burn it or whatever it takes. I promise. Course then I'm going to offer to buy the car for whatever you told your wife it cost. :devilgrin:
 
JP I still need to work out the fine print
Early morning off to bed
Phil
 
Mike don't get me starting on that rear disc set up, I just helped Dick May take a set of Sentra rotors and turn half of them into dust :smile: Fred T. was there and was amazed at how much work had to be done to the rotor to make it work, needless to say he wants the WC set up now :smile:

The big front brake set up is nice and needed on the race cars, I don't really see a need for it on the street, and if a guy wants to go with big brakes on the street for the heck of it, then Peter May has some really nice set up that are well beyond what we can do in SCCA rules, but you street guys are not bound to those rules. When I drove the Huffaker Bugeye, that was the first time I had to race on the stock brake set up, I killed the brakes the first weekend in the car, but afterwards made some cool brake duct cans and the brakes stayed under me fine after that, I'll have to use the same set up in vintage to be legal, what I will miss is my WC rear disc set up, arg, having to deal with double hubs and a drum brakes again. The issues for the street on all the rear disc set ups is there is no emergency brake which can be a another PITA for street car. The number 1 probalm i se with Bs and Spridget when they overheat their brake in the mountian curvy stuff is the rear breaks were out of adjustment, while the rear does not do that much of the totla braking , take it out of the equation and your front brakes will overheat in aggressive curvy street driving. my advice would be keep those rear drum brakes clean and adjusted.
 
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