14 replies to this topic

[ibby4585]

Hi.

I'm just seeking clarification on the front and rear subframes for my mk1 mini 850 1967. I've looked under frequently asked questions and I can only find auto and manual queries.

I have a mk1 mini and both subframes are pretty bad. I want to replace them and build the new ones up so I can just swap them over when I replace the engine and brakes.

The plan is to replace the hydrolastic with dry suspension and fit disc brakes to the front with a 1380 motor.

Am I right in thinking as long as i get both the later dry suframes front and back they will fit my mk1 with my suspension plans?

Cheers
Kris

[miniman_7]

I believe that you will be ok with new subframes.
Bear in mind that the new type will need the rubber mountings that will be missing from the originals, and also that the tower bolts will be different.

Just been looking at your project thread. Looks like you have a similar collection of rust as me!

[cooperrodeo]

I think you need to give the tower bolt issue some thought. Your crossmember will have provision for the twin tower bolts of a wet subframe and it will have tubes within the box section to prevent it squashing when the bolts are tightened up. There will not be a tube for the single hole through which the single tower bolt of the later subframe will pass. I am not familiar with a single tower bolt shell but I imagine that the hole is strengthened with a tube. The hole in the wet Mk1 shell might also be too large as it normally accommodates the hydrolastic displacer pipe and protective nylon tube.

I converted my Mk2 to dry but used a Mk1 dry front subframe. I used a much later rear subframe c1995 without any problems.

[ibby4585]

So easiest option is getting a mk1 front subframe and a later rear subframe? So will the early mk1 front subframe accommodate dry suspension?

Cheers

Kris

[miniman_7]

It will need to be a dry subframe.
The hydrolastic subby will not accomodate the rubber cones correctly.
You will also need different upper arms for the front

[Cooperman]

Later front sub-frame will most definately not fit a Mk.1. The fitting of the Mk.1 sub-frame was completely different, and much better, than the later ones.
The tower fittings on the Mk.1 have two long bolts each side, the rear fittings on the front frame are fitted at the 'kick' line of the floor with 2 off 5/16" UNF bolts and nuts per side and don't cause the panel fatigue failure from which the later cars can suffer. The front fittings are just bolts and nuts with no rear-drop fitting.

[mk1leg]

speak to either minimachine or minimail.............

http://www.m-machine.co.uk/

http://www.minimail.co.uk/

they have a huge mk1 spares stock...................

[ibby4585]

So how is everyone updating hydrolastic suspension to dry suspension? I'm confused now? (

Kris

[Cooperman]

If you have a 'dry' Mk.1 front sub-frame, you just fit the rubber cone springs and aluminium trumpets (or Hi-Lo's) and change the top arms for dry ones. In fact you can use hydro top arms if you have Hi-Lo's to set the height. Some say the different suspension ratio is better for high performance driving, but that may be heresay.
If you have a hydro front frame you just knock back the hydro locating tabs which are up in the tower, or grind the tabs away so that the rubber cone springs will seat correctly. There is a 1/4" spacer at the tower top to body cross-member position on the hydro cars. Keep this if using a modified hydro sub-frame, but delete it if using an original 'dry' frame.

Edited by Cooperman, 11 October 2011 - 07:10 PM.

[pdaykin]

You need an early front sub-frame with the twin tower bolt mountings not the later single bolt.

The early front subframe is significantly different to the latter type - I think Nick at Mini Bitz in Sheffield will be ale to sort you out.

The latter subframe does fit and I use them as a temporary install to enable me to move the shells around while the correct subframe is being refurb. It shouldnt be used on a permanent basis as it will not fix at the rear correctly - the early sub-frames are solid mounted.

On the rear I you can get them without the mountings for the latter style exhaust - you do not need the very latest type of rear subframe

As also mentioned, you should also consider changing the front top arms for dry ones - if you the Hydro arms the steering will be quite heavy.

At the rear, the radius arm/handbrake quadrant and handbrake cables are different between hydro and dry cars. If possible, you should try and make sure that you use either all dry or all wet components - ideally all dry.

[ibby4585]

Er I think I follow you. I think I will just remove the original subframes and go from there. This is my first mini rebuild and I don't fully understand what's needing to be done.

Cheers

[Cooperman]

I don't see why fitting hydro top arms to a dry car would make the steering any heavier. The overal length of both types of top arm is the same, the only difference is the position of the knuckle joint cup which is slightly nearer to the mounting pin thus increasing the ride height to trumpet length ratio which is 5:1 on a dry top arm and about 5.5:1 on a hydro top arm (this from memory).
There really is no big issue with making any Mk.1 into a dry suspension car. I always do it on historic rally cars for reliability and serviceability.
Just get a Mk.1 sub-frame, dry or hydro, take a good look at it, then come back on here for sub-assembly and installation advice.

[midridge2]

because both subframes are in need of replacement you need a dry suspension front subfame, any dry front subframe with the 2 bolts at each side that go throught the crossmember will fit, you really need as said new rubber cones and trumpets as you are converting to dry but you will also need to replace the top arms with dry ones as they have the bolts in them for new front shockers that you will need and the top mounting brackets to go with them, regards the rear subframe any dry ones will fit but you need new cones and trumpets and quadrants and handbrake cables and new radius arms because the hydrolastic ones dont have fittings for rear shocks.

[cooperrodeo]

There is a 1/4" spacer at the tower top to body cross-member position on the hydro cars. Keep this if using a modified hydro sub-frame, but delete it if using an original 'dry' frame.

er ... I think this is the other way round. The dry tower needs the spacer. The wet tower is slightly taller with no need for a spacer. This also means the dry tower bolts are slightly longer. The tower bolt threads are also different between wet and dry.

[Cooperman]

Maybe, it's 15 years since I last did this when a 1967 hydro Cooper 998 was built into a 970 Cooper 'S' for competition by my son. I was sure we used the hydro sub-frame and fitted it with dry cones, Hi-Lo's, etc, and that a 1/4" spacer was fitted. Can't check as the car was sold a long time ago. My 'S' has a dry sub-frame although it was 'wet' as built, so I guess I need to see if it has a spacer plate, which I'll do tomorrow. I'll also check on my Innocenti which is dry.