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Thread: Bugeye drum to disk brake conversion

Discuss the Austin Healey Sprite and the MG Midget. Two different but similar cars sometimes referred to collectively as the Spridget.

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    Obi Wan
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    Bugeye drum to disk brake conversion

    Hi all,
    I restored my 59 bug a few years ago. I tried to keep it as original as possible. The only changes I made were to make it more practicle. After driving it over the last few years, I really don't like the stopping capability of the front drum brakes and was thinking of moving to disk brakes. My first step is finding the parts. Does anyone have a complete list of parts I would need and know what year Sprites I can get these parts from? How difficult is this to do? Are there any articles you are aware of that takes you through the steps? Any help on any of these questions would greatly be appreciated.
    Kevin
    Last edited by ichthos; 05-12-2019 at 11:58 PM.

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    Darth Vader Rut's Avatar
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    Re: Bugeye drum to disk brake conversion

    Kevin, look for the front suspension/brakes from a disc brake car and I would go for a later Midget. Make sure you get the later steering arms as well.
    Rut
    Rut, '60 Bugeye, '70 MGB, '62 TR4, '66 TR4a IRS, '67 TR4a IRS, '68 TR4a IRS, '72 TR6

    When I went to school, they asked me what I wanted to be when I grew up. I wrote down 'happy'. They told me I didn't understand the assignment, and I told them they didn't understand life. John Lennon


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    Yoda
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    Re: Bugeye drum to disk brake conversion

    Rut. Are the early steering rack's compatible with the late tie rod end's? Seemed like that was a problem. Other than that everything just bolts up. Should change to the 3/4" bore master for best brakes and, not as important, different rear wheel cylinder's or late brakes.

    Kurt
    65,66 Midget
    57 Berkeley, MGA
    Working on quality rather than quantity

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    Darth Vader Rut's Avatar
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    Re: Bugeye drum to disk brake conversion

    Quote Originally Posted by nomad View Post
    Rut. Are the early steering rack's compatible with the late tie rod end's? Seemed like that was a problem. Other than that everything just bolts up. Should change to the 3/4" bore master for best brakes and, not as important, different rear wheel cylinder's or late brakes.

    Kurt
    Kurt, iirc the TREs will need to be changed to fit the later steering arms and yes, the 3/4 mc will be needed and you can also change to the later rear plates with their wheel cylinders. Basically you are changing from a Bugeye brake system to a later Midget one.
    Rut
    Rut, '60 Bugeye, '70 MGB, '62 TR4, '66 TR4a IRS, '67 TR4a IRS, '68 TR4a IRS, '72 TR6

    When I went to school, they asked me what I wanted to be when I grew up. I wrote down 'happy'. They told me I didn't understand the assignment, and I told them they didn't understand life. John Lennon


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    Obi Wan
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    Re: Bugeye drum to disk brake conversion

    So, would any year midget with disk brakes work? What years would I be looking at?

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    Moderator drooartz's Avatar
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    Re: Bugeye drum to disk brake conversion

    Here's a writeup I did a few years ago when I converted my first bugeye. Pictures are missing (need to finish it one of these days) but it might have some helpful tips for you:

    https://docs.google.com/document/d/1...it?usp=sharing

    I'm using the standard early steering rack tie rod ends with the steering arms from the disc brake Spridgets that used the same rack. Don't have the part numbers in front of me right now.
    Drew Frink
    '59 RHD Frogeye Sprite - "Penny" sleeping for now
    '66 RHD Morris Minor - "Maggie" awaiting a non-cracked transmission
    '70 RHD MGB - driving in 2019?
    '19 Triumph Bonneville T100 - good to have one that runs

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    Re: Bugeye drum to disk brake conversion

    I followed this advice as well and grabbed the eBrake rods from later Spridget donor and they fit perfectly and did not need cutting and splicing.

    Getting Master Resleeved in Brass eliminates issues with MC bores pitting and rusting. Again Gerard is the go to guy for this work. 3/4 Masters are now available but resleeving solves a common source of failure with Spridget brakes. Gerard reported to me the hes resleeved some of these cast iron 3/4 masters already due to putting and cylinder bores rusting. Reskeeving in brass is a permanent solution.

    i used later backing plates and 3/4 wheel cylinders and braking bias is perfect. Later backing plates are a more modern design and are IMHO easier to keep adjusted.

    It it is possible to use the Dual Master off of a later Spridget but it does take a lot of cutting of the top of the footwell to get it to fit.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Re: Bugeye drum to disk brake conversion

    Wanted to mention that on another forum a gent from Aussy said that using the rear wheel cylinders from, I think, a Riley will give you the correct brake bias with the stock BE rear brake system. I had a BE with front disc's that hadn't had the master changed or the rear brakes upgraded. It was OK to drive and an improvement over the stock drum's. Took a pretty firm stomp on the brakes but driveable.

    Kurt
    65,66 Midget
    57 Berkeley, MGA
    Working on quality rather than quantity

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    Yoda Jim_Gruber's Avatar
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    Re: Bugeye drum to disk brake conversion

    Lew McCallan from Chicago, soon to be returning to Aus, used the Riley 3/4” wheel cylinders. My issue is WTH do you find parts for Rileys a car never imported to the US. I pulled parts from a donor car and grabbed backing plates and eBrake Rods as well. It worked for Lew but I redid Bugsy’s rear brakes before I had the opportunity to trade parts and meet Lew halfway between Dayton and Chicago in parts swapping trips.

    I will confirm Bugsys brakes are easy to modulate and you don’t have to stand in them to get him stopped. 3/4 rear wheel cylinder is the way to go.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Obi Wan
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    Re: Bugeye drum to disk brake conversion

    First of all, thanks for all the information. A little bit overwhelming I admit. It looks like I can use a Sprite or Midget from 62-67. I am going to have Gerard rebuild my spare master cylinder so that the one side has the 3/4" bore. The main reason is I don't want to alter anything that can't be changed back. I am not going to change out the rear drum brakes. From there I guess my main mission is to find a basket case car to remove what I need. I am unclear-do I have to change out the steering rack too?

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    Re: Bugeye drum to disk brake conversion

    You can use the Bugeye steering rack.
    "Age considers; youth ventures." Rabindranth Tagore
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    Obi Wan
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    Re: Bugeye drum to disk brake conversion

    Thanks on the steering rack info. I tried going to Gerard's Garage, but was not able to contact him or get prices. When I push the contact hyperlink, it just says error, file not found. Could I get some help on this?

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    Re: Bugeye drum to disk brake conversion

    When the rack was changed the tie rod ends were changed as well. I don't remember if the BE steering arms will fit the disc brake spindles or not. If they will, all that would be necessary to use any disc brake spindle would be to change the arm's. Seems like the BE arms don't fit though. Memory......someone's whose is better than mine needs to chime in.
    65,66 Midget
    57 Berkeley, MGA
    Working on quality rather than quantity

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    Yoda HealeyRick's Avatar
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    Re: Bugeye drum to disk brake conversion

    It's been about 30 years since I did this swap so memory may be a bit fuzzy. I used all the parts from the later Spridget and used the dual master cylinder that came with the earliest disc brake cars. Steering arms were from the later car attached to the bugeye rack. I kept the original bugeye rear brakes and cylinders and never had any problems. Gerard's email is pixelsmith@gerardsgarage.com
    Rick

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    Re: Bugeye drum to disk brake conversion

    Steering arms to use with a BE Rack are part #'s BTA648 and BTA649. I'd replace the Tie Rod ends as well. They should match the year of the rack. Donor Car could be from 58 - 72 when they changed over to the Triumph Rack. If you grab parts from a later Spridget you likely will need to change the rack. It used to be about 15 1/2 threads showing to get alignment close. New TRE's are closer to 7-8 threads I found on Bugsy.

    I've recommend having both sides of the Master resleeved. That way you won't need to worry about pitting and rust in the Master in the future.

    Clean up the swarf out of the rack mounting bolt holes. Those bolts in there are a specific length as when I swapped out for new Bolts, they bottomed out and I could not get the rack tight. There will be crap in those mounting holes. I used a tap to clean out and a piece of bicycle inner tube on the rack cap mount.

    While apart, new wheel bearings, SS Brake Hoses. I replaced all of the components that normally wear out after 60 years. I added new Shocks from Peter C and replaced both A- Arms and added a Major Suspension Kit and a Front Stock Sway Bar that came from the Donor car as well. Sway Bar Bushings got replaced as well. Yes it was a case of while I'm in there...but Bugsy tracks like he is on rails. And with the 5 Speed and new 1,326 cc engine, he drives and tracks comfortably at 80+ mph. Not cheap but oh does he drive nice.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Re: Bugeye drum to disk brake conversion

    There is a kit: https://bugeyeguyparts.com/collectio...conversion-kit $2,400 without the M/C
    Rick

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    Re: Bugeye drum to disk brake conversion

    For that price ask on MGEXP, AHEXP, and this forum who has a tub rusting away for parts. Spindles are the key part you need. I bought new calipers and rotors. Finds tub and pull the needed parts. Someone on one of those lists orCraigs list will be able to provide you the needed donor parts.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Re: Bugeye drum to disk brake conversion

    Hi Jim and ichthos.

    Actually, for my Bugeye I plan to use Morris Minor 3/4" bore rear wheel cylinders to get better brake "balance" and feel with the 3/4" Master Cylinder. The advantage is that you do not need to change the backing plates or handbrake rods, as the Morris Minor wheel cylinders are same physical fit as the Bugeye 7/8" cylinders. Since you are reaching out to Gerard for the MC, I believe he can provide these as well.

    On ahexp, there are numerous threads on this conversion and in one recent thread https://www.ahexp.com/forum/the-spri...90/#msg-211790 I posted this.... still available on eBay, a complete setup including steering arms for reasonable money.

    I found this on eBay that includes most of the parts for $300, including steering arms and calipers & discs. Probably the way to go. https://www.ebay.com/itm/MG-Midget-A...ty!60047!US!-1

    or for wire wheels

    https://www.ebay.com/itm/Pair-Front-...AAAOSwBgZbznNa

    Cheers
    Lew

    Quote Originally Posted by Jim_Gruber View Post
    Lew McCallan from Chicago, soon to be returning to Aus, used the Riley 3/4” wheel cylinders. My issue is WTH do you find parts for Rileys a car never imported to the US. I pulled parts from a donor car and grabbed backing plates and eBrake Rods as well. It worked for Lew but I redid Bugsy’s rear brakes before I had the opportunity to trade parts and meet Lew halfway between Dayton and Chicago in parts swapping trips.

    I will confirm Bugsys brakes are easy to modulate and you don’t have to stand in them to get him stopped. 3/4 rear wheel cylinder is the way to go.

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    Yoda Jim_Gruber's Avatar
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    Re: Bugeye drum to disk brake conversion

    Thanks for correcting me Lew. 3 weeks in the new house Wednesday. Back to work on Bugsy teardown for paint hopefully next week.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Obi Wan
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    Re: Bugeye drum to disk brake conversion

    Just emailed Gerards and one of the companies on ebay. I will let you know what I find.

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