140 series brake booster in 122S?

I am evaluating some long term performance modifications for my 1966 122S wagon, and right now I am looking at the braking system. I gave everything an overhaul about 4 years ago, but I want to consider some upgrades.

At one point, my car had a Girling booster, but it was removed after it failed. There is a Lockheed booster that Volvo sold as a replacement; I currently have one in my possession, but it may need a rebuild. I also know that 1969 and 1970 122s sold in the rest of the world received a 140 series brake booster and master.

There is a topic on VClassics where Cameron notes the superiority of the 140 setup, and mentions that modifications to the firewall, pedal assembly, and hydraulic lines are necessary. I don't have access to a 140 booster at this time, so I just want to see if anyone has done the swap and can show me what the changes would be.

Thanks in advance!

If you can find someone with a 68. That should also have the dual circuit system like the later cars. You could install a dual circuit master cylinder and just have the front system on a booster. If you want to get an idea of the parts involved for an oem setup browse the parts catalogs on gcp.se.

IMHO, the stock front rotor/rear drum brakes system for the 1962-1968 122 and 1800 Volvos is more than adequate especially if there is a functioning original style brake booster. The only thing I don't like is the single circuit brake master used on the pre-1968 models.

In 1968, 122 and 1800 Volvos made for US market came with a dual circuit brake master that bolts in place of the single circuit brake master. And now that a new reproduction dual circuit brake master for the 68's is now available, it's easier to convert your 1966 122 wagon to a dual circuit master cylinder.

Modifications are needed to convert to the 1968 dual circuit master so it's not a bolt in conversion but it's a lot less work than going to the 1969/70 system or even to just the 1969/70 122/140 brake booster and master cylinder.

You will need a lot more than just the 140 brake booster if you are going to upgrade especially if you want upgrade to the entire dual diagonal brake system that came on the 1969-1970 122s.

We had to this conversion about 5 years ago when we restored a 1969 122 for a customer.

The 1969 122 body was badly rusted and since there were no 1969 or 1970 bodies available, we had to transfer everything including the entire braking system to a shell from a 1967 122.

We had to remove and transfer parts that were welded to the body. The brake/clutch pedal box and the brackets for the dual brake proportioning valves had to be welded on to do the conversion.

The brakes in the 69/70 models are really good. If doing a full rebuild there is merit in converting to the late brakes

dl242gt said:

If you can find someone with a 68. That should also have the dual circuit system like the later cars. You could install a dual circuit master cylinder and just have the front system on a booster. If you want to get an idea of the parts involved for an oem setup browse the parts catalogs on gcp.se.

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It's a dual circuit, but it's not triangulated like the later cars. 1968 was simply a front/rear split, which - as Eric mentions - is really pretty simple to retrofit to an earlier 122. Stock setup for this approach was to boost the front only.

I did this conversion on my 123GT decades ago. The 140 came with a normal vacuum booster mounted on a long snout to the firewall. I modified the snout from the 4 bolts the 140 uses to the 2 bolts the 123 uses. As I recall, I cut the flange off, but just the flat part, and welded on a flat plate and a couple of tubes for the bolts, as they go thru the formed part of the snout. It worked out like it was meant to be there.