Tell me about brake dive in MGBs

So I've never driven an MGB, but I'm currently working on a kit car that uses MGB front suspension, and the thing has what seems to me an excessive amount of brake dive. Is this normal, or are the shocks worn out, or something else?

Build thread coming soon.

Cant say as it is an issue with the 67 that I have.

Don't MGB have lever arm shocks, or am I thinking the A

Both have lever arm shocks. Not an issue in any MG I have. Power, yes, but the brakes are reasonably good for the era.

Did you check the oil level in the shocks?

You're purposefully using an MGB front suspension?

I remember reading once that BL raised the suspension height late in the MGB's life as a lazy method of complying with minimum bumper height legislation. If one of those is the donor, could be the issue...

Never experienced brake dive on MGBs I have owned or driven when I was a British car mechanic. Does it bounce back quickly and continue to bounce when stopped?

What are you using for rear brakes? Are you using an adjustable proportioning valve for rear brakes?

Keith Tanner wrote: You're purposefully using an MGB front suspension?

Had to laugh!

The MGB suspension was actually used in some early Cobra kits. The geometry is not terrible which is good because it is also not adjustable. Kingpins are not my most favourite thing either since they are always worn out and $$$ to rebuild.

It has the virtue of being self contained, narrow and only requires 4 bolts to attach.

Apis Mellifera wrote: Did you check the oil level in the shocks?

Also check what oil is in them. Sound like someone may be trying the old 3in1 trick.

NOHOME wrote: It has the virtue of being self contained, narrow and only requires 4 bolts to attach.

Met a guy using an Opel GT front suspension in a Hillman Delivery Wagon hot rod for the same reason. All one piece, self-contained also. Couldn't really understand it as the transverse leaf spring does have limits.

NOHOME wrote:

Keith Tanner wrote: You're purposefully using an MGB front suspension?

Had to laugh! The MGB suspension was actually used in some early Cobra kits.

We have a winner! I'm working on an Arntz Cobra kit from about 1981. My buddy just bought it and said the brakes suck, which they do. "System" sizing is horrible, but I'm fixing that. Anyway, I have no prior experience with MGBs, and this thing dives a bunch in braking. It has the OE type MGB dampers on it. I will research how to service them. Thanks!

FYI: There are kits available to replace OEM shocks with tube shocks and adjustable control arms.

I've never noticed it in an MGB, but I wonder if the suspension was "improved worse" by the kit manufacturer. If they canted the whole frontend back in an effort to increase caster (probably the only way to do it with kingpins) then this will introduce a measure of pro-dive as an unintended consequence.

My '71 B doesn't dive (converted to tube shocks 25 years ago). I don't think the front brakes work much these days, which might explain a lot.

If memory serves, when used on the Cobra kit, the hot front brake ticket involved Granada front brakes in some way shape or form

NOHOME wrote: If memory serves, when used on the Cobra kit, the hot front brake ticket involved Granada front brakes in some way shape or form

Might be the first time "hot ticket" and "Granada" have been used together.

Ln the old days, racers replaced the shock oil wit 90wt gear oil or something similar.

If in good shape, the MGB front suspension is more than adequate. If trying to used old parts of unknown condition, then all bets are off.

As to the shocks, putting in heavy oil is a bodge for worn out shocks. Rebuilt units are not that expensive. A full front end rebuild hub to hub with new springs and shocks will run about $1500 in parts.

I can't say I was that impressed with the MG front end I tore off my car. Unbelievably heavy with bolted-together control arms - I can see why an old kit car might use it for convenience, but it sure wouldn't be my first choice for a project today.

NickD wrote:

NOHOME wrote: If memory serves, when used on the Cobra kit, the hot front brake ticket involved Granada front brakes in some way shape or form

Might be the first time "hot ticket" and "Granada" have been used together.

Several kits use mustang II/pinto spindles, granada rotors fit and give you an 11" vented rotor - combine with chevy S-10 calipers was a common kit cobra/hot rod combo. Don't think that's the same as this car. I'd be looking at shocks and springs as the culprit.

iceracer wrote: Ln the old days, racers replaced the shock oil wit 90wt gear oil or something similar.

Actually those of us who understood the shock absorbers bought shock fluid from motorcycle shops that came in various weights up to 50 weight

Depending on weather conditions and track I would use anywhere from 10 weight to about 30 weight. Sway-bars and spring rates varied Among Various MG models and were extremely easy to change. The same suspension was used from MGTD of 1950 through the 1980's because it did several things very well. One of which was anti-dive without the typical lousy camber gain curve that entails. Later versions had a simple 4 bolt mounting which afforded easy spring rate/ sway-bar adjustments and the ease which suspension damage can be dealt with

Brakes for the MG front suspension are easy. Contact Wilwood and ask them for the same brakes they put on Jay Leno's V8 MGTD. In fact there is a Video of it on U-tube

wlkelley3 wrote: Couldn't really understand it as the transverse leaf spring does have limits.

Don't tell that to GM. ;)

atm92484 wrote:

wlkelley3 wrote: Couldn't really understand it as the transverse leaf spring does have limits.

Don't tell that to GM. ;)

GM didn't use the spring as a stressed member. Old Cobras (except 427s) used it as the upper control arm. No idea how the Opel GT used it.

(wait... was Opel part of GM when the GT was designed?)

In reply to iadr: Thought of that after I posted. Still thicker than the stock oil I guess.

I only got this info second hand.