This is a 1942 M3A1 Stuart tank in ready for use condition. Here I leave a bit of history about Brazilian Stuart tanks taken from www.globalsecurity.org:  

At least 20 American M3 Stuart Light Tanks (out of a promised 65) were received in 1942 and used to replace armor then available in Brazil. A further 200 were acquired between 1944 and 1945, both in the M3 and M3A1 versions. By the 1970's it was becoming increasingly difficult to find spare parts for these tanks, so a decision was made to modernize part of the M3A1 series. The decision to modernize vehicles so old was a political one: by 1977 Brazil had denounced the US-Brazilian military agreements, so no more obsolete (and cheap) vehicles were available from North American sources.

In the early 1970s Bernardini rebuilt two American M3A1 Stuart light tanks for the Brazilian Army. Technical control of the project was under the direction of the Brazilian Army Research and Development Centre. The modifications included replacing the armor above the tracks by new sloped armor provided by the Biselli company, replacement of the original American gasoline engine with a six-cylinder Saab-Scania diesel developing 280 bhp, new volute suspension designed by the Novatracao company, new turret with a French DEFA D-921A 90 F1 90mm gun as fitted to the Panhard AML (4×4) and other light AFVs, and a fire-control system designed by the D F Vasconcelos Company. The vehicles weighed 15,000 kg, had a road range of 450 km and could ford to a depth of 1 meter without preparation.

Following prototype trials, the Brazilian Army ordered 100 M3A1 light tanks to be rebuilt to the new standard. The first 80 vehicles were modernized between 1975 and 1978. These were delivered to Cavalry Regiments under the designation X1, with final deliveries made in 1978. The new car, known as CC MB1 (Combat Car, Brazilian Model nr. 1) or X1A, remained in service until the 1990's.

This tank runs well and everything is in order. Some features are: deactivated weapons; reliable Detroit diesel engine; original transmission; good tracks; new paint. More information at: MILWEB.